I discovered a way cheaper alternative to Lululemon in an unexpected place

While I was walking down Sixth Avenue in Manhattan, I came across a blast from the past.

I looked into the store window and tried to remember the last time I went into an Old Navy.

Out of curiosity, I decided take a quick five-minute look.

But what I discovered was compelling - and completely surprising.

As I walked past the jeans and the back-to-school outfits for kids, I came across the activewear section in the back. 

The selection of items looked as though I walked into a completely different store. 

The yoga pants, tank tops, sports bras and even sneakers were well-designed. They looked really cool.

I started browsing through the items, feeling the fabric and I thought to myself, "this is easily comparable to Nike or Lululemon." 

Even better, they were affordable. 

Compression crop pants that are almost identical to the overpriced Lululemon were just $18, a fraction of the yoga retailer's prices. 

This was a whole new world.

I began sifting through the other items: $12 for a top that looked just like one I had from Lululemon, $24 for sneakers with no obnoxious label, $24 for a sleek quarter-zip pullover. 

Intrigued by my new find, I researched more about Old Navy's activewear line. Current Old Navy interim CEO and EVP of global product, Jill Stanton is much to credit for the recent transformation. 

Stanton joined Old Navy in 2012 after coming from a 14-year position as Nike's vice president and general manager of global apparel. Her experience with Nike has contributed to making Old Navy's athletic apparel more competitive in the market. 

Since 2012 - with the addition of Stanton and former Old Navy CEO, Stefan Larsson - Old Navy saw noticeable sales growth. Last year, Old Navy reported same store sales growth of 5% while Banana Republic's sales were flat and Gap's fell 5%.

Old Navy's current ad campaign for active wear is "Built for Play" with the intention that the clothing line is family friendly, falling in line with Gap Inc.'s values.

And I'm not the only one who has noticed Old Navy's new look:

It's unlikely that Lululemon affectionados will decide to start shopping at Old Navy instead. 

But it's a great option for anyone on a budget.