I spent $299 to fly as much as I wanted. I love the idea of traveling on a whim, but the spontaneity isn't for everyone.

• Frontier Airlines has an all-you-can-fly flight pass called "GoWild!" that costs $1,999 annually.
• I bought the cheaper $299 seasonal subscription and recently used it to crisscross the US.

Frontier Airlines' all-you-can-fly pass is an interesting concept that comes with a major catch.

Called "GoWild!," the subscription-based program gives members exclusive access to heavily discounted flights — $0.01, plus taxes and fees.

The bookings can be made the day before for domestic flights or 10 days in advance for international, with the option to pay an early booking fee for dates beyond that. Luggage, reserved seats, snacks, and drinks other than water still cost extra.

Hypothetically, this means one could wake up one morning and, on a whim, go hop across Frontier's route map for as low as $15 per leg with just a personal item.

It sounds too good to be true, so I decided to test it out using Frontier's $299 unlimited fall and winter pass. The seasonal price I paid is discounted from $999, while the annual GoWild pass costs $1,999 and the monthly subscription costs $149.

I hit three cities across five days, spending $60 total on the last-minute flights. There were early mornings and late nights, some moments of uncertainty, and hours of flying on Frontier's uncomfortable planes.

All of these things I can emotionally and physically handle, but I know this type of spontaneous travel can be draining for others.

After using the pass, my gut was right. I found that GoWild can be extremely frustrating to use if you aren't flexible or willing to get creative. But for others, it may be a golden ticket.

Over 4,000 miles in five days for $60

Frontier's GoWild pass offers unlimited flights across its entire network, which touches the US, Mexico, and the Caribbean.

The seasonal pass I bought is only good for the fall and winter and lasts from September 2 to February 29, minus some blackout dates.

I started my trip in Austin, Texas, on a Sunday after a friend's wedding. I had a few travel goals in mind: go to Sphere in Las Vegas, ride the Brightline train in Florida, spend a day exploring whatever city I could get to along the Northeast Corridor, and then make my way home.

My routing ended up being Austin to Vegas to Orlando to Miami to Philadelphia to Stamford, Connecticut. The legs to Miami and Stamford were via trains.

I bought my first leg to Vegas about a week in advance thanks to the early booking option to ensure I'd at least get out of Texas. I was also worried that the newly-opened Sphere would be so popular that tickets would sell out.

I felt guilty because I think early booking defeats the point of GoWild, but the peace of mind was worth the extra $15.

The other two legs were booked at the lowest rate, so I paid $15 to Orlando and Philadelphia and $30 to Vegas for a total of $60 on three flights. Without the pass, the flights would have cost about $260, the most expensive being $123 to Orlando at the regular fare.

By the end of my GoWild trip, I got a lot done and even saw some friends along the way thanks to them answering my random last-minute phone calls.

I personally enjoyed piecing together the trip and having various options to work with, but I also loved that I could potentially switch up plans on a whim if I wanted.

But I realized the too-good-to-be-true pass has a few pain points that make it only really useful for certain lifestyles.

The "unlimited" flight pass has its limitations

One of the biggest concerns about GoWild is actually getting anywhere at all.

Not only are there blackout dates, but it's not uncommon for Frontier to have nonstop flights listed but no GoWild seats available for purchase.

This could force people to ditch paradise destinations like Cancun for a completely different city in a random place, like Ohama, for example. Not that a spontaneous trip to Nebraska can't be fun, but it's not the beach getaway one may have expected.

Plus, last-minute GoWild seats to the Caribbean are difficult to snag as found by a Wall Street Journal reporter who tested the pass in June.

Only booking one day in advance for domestic flights makes travel planning basically impossible because hotels and activities can't be booked until the flight is.

I found this to be an issue on my trip with hotels being more expensive than expected. The ghost tour in Philadelphia I wanted to go on was sold out by the time I was able to book my flight.

Frontier doesn't always have the best flight schedule

I didn't have many options leaving Austin except a 10 p.m. flight to Las Vegas as there were no nonstops to any East Coast city and I was avoiding layovers. I wasn't thrilled about the late departure and spent 10 hours at the airport, but that's part of the experience.

After a full day of touring around Las Vegas, I was hoping to sleep in the next morning and then take a red-eye flight to Florida that night. This would give me at least one night of full rest, but alas, I had to bend to another curveball of Frontier's flight schedule.

Surprisingly, on the one day that I wanted to fly to Orlando, Frontier had only a 6:15 a.m. flight — nothing later. And there was nothing nonstop to other hopeful destinations like Miami, Philadelphia, or Washington, DC.

Any layover would mean I'd have to leave Vegas early anyway, too.

So, I sucked it up and trudged through another sleepless night after leaving the Sphere at 11:30 p.m. I guess that's my fault for assuming Frontier's regularly scheduled red-eye was operating, though.

For the flight to Philadelphia, I actually originally booked the 6:10 a.m. flight so I could spend the day touring.

However, after getting up at 4:30 a.m. to fly to Orlando, making my way down to Miami via Brightline, having dinner with a friend, and then getting to the hotel after 9 p.m., I was beat.

I ended up waking up at 2 a.m. so stressed about the flight that I canceled the early leg and rebooked on the 1:11 p.m. for another $15 instead, which thankfully still had GoWild seats available.

There was no cancellation fee and I didn't get the original $15 refunded, which was fine. But I also lost a day of exploring Philadelphia.

I restricted myself to a personal item

Only bringing a personal item is an individual choice, but I was trying to book the cheapest GoWild flights possible and that meant forgoing a carry-on bag, which cost over $60 for each leg.

I brought a regular-sized backpack that had a pocket in the back for my laptop. I packed it so that nothing bulged out and it fit perfectly inside Frontier's size checker.

I'll admit that I had to pack and repack several times, and I had to ditch a lot of outfits that I wanted to bring with me.

Bringing only a personal item ended up being extremely challenging, so I recommend just paying for the carry-on if you think you'll need it.

If you do opt for the free option, be warned: an agent visually checked every personal item during boarding during all three flights and forced those that looked too big into the size box. The maximum allowed dimensions are 14×18×8 inches.

I guess mine never sounded the alarm as I just walked past with no issue every time, but others were pulled out of line and had to pay up.

Finding GoWild seats is a lot of tedious guess-and-check

The process of searching and booking GoWild seats is a cumbersome task. The flights can only be bought on Frontier's website, not its app, and customers have to check each one by one.

It's a lot of guess-and-check, and I hate how tedious it is.

Fortunately, some computer-savvy individuals independent of Frontier launched "The 1491 Club" which lists every single GoWild seat available from today until about two months out.

You can see every flight departing and arriving in certain cities with the price and number of stops listed. The website will even link directly to the exact flight on Frontier's website.

This tool is honestly life-saving. And while I don't love paying the steep $15 per month for it, it saved me a lot of effort when trying to Tetris together my GoWild itinerary.

Getting home proved tricky

The hardest part of my GoWild adventure was crafting a way home once I realized using Frontier isn't ideal for those of us living in no-mans-land Connecticut.

I live near Stamford in the south of the state and the closest airports are LaGuardia, Islip on Long Island, and Hartford in northern Connecticut, all of which are at least an hour's drive from my house.

When I bought the pass, I initially planned to use Stewart International Airport in New Windsor, New York, 40 minutes away, but Frontier has sadly since shut down operations there.

The only nonstop to New England from Philadephia is to Boston, no hopper options. Granted, Philadelphia isn't too far away and I ended up taking a two-hour Amtrak directly home for $40.

Though not ideal, I could have also booked a cheap bus. However, if I was further away and flying was the only option, I'd be restricted to those far-away airports that are a hike away from home.

I could save time by driving, but then I'd be locked into returning to the same airport, which would make using GoWild even tougher.

My advice is if you don't live near a Frontier hub or focus city, GoWild will be nearly impossible to use unless you're willing to add drive time, parking fees, or Uber or train fares.

GoWild is most realistic for those with remote or flexible jobs

Overall, I think $1,999 for the year would require much more GoWild commitment than I could muster, but I would easily get the $299 seasonal option again.

Despite the less-than-favorable flight times, I managed to check off my list of cities to hit and things to do. This was surprising considering the horror stories I'd read online.

While I had a good experience, there are still a lot of limitations to the "unlimited" flight pass, and the costs can add up.

Personal items that bulge just a little too much may be subject to Frontier's hefty carry-on fee. Or, you may opt to pay extra for more luggage or legroom.

There's also no guarantee you'll get to your desired destination until the day before unless you fork out even more money for an early booking fee. This uncertainty can be stressful.

But for those who love to travel on a whim, the concept of not knowing your next move could be a dream adventure.

Spontaneous digital nomads or freelancers would likely get the most out of the pass. I have a remote job, so I could make it work if I restricted touring to evenings and weekends.

I'm sure there are a lot of people who could make weekend getaways via GoWild work, too. But it'd come with risks like getting stuck somewhere and missing work — at that point, I don't think it'd be worth the hassle.