I started my T-shirt-printing side hustle with a press I bought on Facebook for $45. Now the business is making $50,000 a month in sales on average.

• Ari Simpson, 39, bought a T-shirt press on Facebook Marketplace for $45 to start her side hustle.
• Simpson started selling T-shirts while working 9 to 5 at a bank.

This as-told-to essay is based on a conversation with Ari Simpson, a 39-year-old entrepreneur from South Carolina, about her T-shirt side hustle. It has been edited for length and clarity. Insider has verified revenue.

I graduated from the University of South Carolina Upstate with a degree in information management and systems in 2007. I work in IT in a bank, where I've been since 2011.

In 2017, I got the itch to create something. In my spare time I started making flyers and invitations for weddings, businesses, or events. It was a mini side hustle that didn't make much — only $200 that year.

I've always been a T-shirt lover, so one day I decided to create my own T-shirts

I dabbled in printing shirts for a couple of years. I created designs on Teespring and worked with a local screen printer to make shirts without a press.

I wanted to launch a T-shirt brand, but I had a full-time job, a husband, and kids. I told myself that everybody was selling T-shirts and that it was nothing more than a hobby that would never make real money.

My husband gave me a pep talk in 2020 that inspired me to start my own business. He told me I could talk about it or be about it. It gave me the confidence to start researching materials or machines I needed to start my own T-shirt business.

I started my business with a $45 heat press from Facebook Marketplace

I got on Facebook Marketplace and found someone selling a used T-shirt heat press for $45. The guy sold us the press and gave us lots of other materials for free because he was closing his T-shirt brand.

Using the heat transfers I'd been given and some old shirts, my husband and I started pressing T-shirts.

I invested in online courses to figure out how to market my new business. I also went to "YouTube University" and watched free videos to learn about T-shirt businesses and followed different brands for market research.

I made a Shopify website and mock-ups of the T-shirts using Canva. It took four weeks from start to finish to get the website built, and I did it from scratch without professional help.

My husband and I spent $55 to buy blank shirts wholesale from S&S Activewear. We made a batch of shirts for our closest family and friends, pressed with inspirational messages such as "Thou shall love thyself first," "It's the peace of mind for me," "Heavy on the self-love," and "I said what I said."

I asked them to buy our shirts, which were $20, and then post pictures of themselves in the shirts on social media.

I officially launched in May 2020, one year after I bought the heat press

My husband and I registered the business as an LLC and began the process of trademarking our business name Tees of Life. We wanted the T-shirts to be wearable positive messages.

For the rest of that year, my husband and I made T-shirts and sold them online through social media mainly. The business made $88,586 in gross revenue in 2020.

I paid $5,000 to join a mastermind group for T-shirt-business owners in 2021 that taught me how to run paid advertising on Facebook. We had weekly group calls and 50 videos that taught us how to increase sales by using ads.

My husband and I spent $100 a month on Facebook ads and got five to seven times the return on spend.

We had to get a small storefront because there were too many boxes in the house. We also bought more heat presses. My husband, my mom, and two of our three children helped us keep up with orders.

The business revenue in 2021 was $608,000. After paying for social-media ads, blank shirts, shipping, and other costs, our profit was around $100,000.

I work eight hours a day at my job and am in the office more often than not. On top of my hours at my job I spent 60 hours a week working in the business.

Even though the business has grown rapidly, I decided to keep my job, because I have a financial plan

When I retire from corporate America, I want to have $100,000 in cash in savings accounts and at least $150,000 in my retirement accounts.

I have a good job that gives me flexibility. My job provides healthcare for our family and retirement benefits. My husband loves his job as a barber and will always continue to be one. His hours are flexible — he works by appointment four or five days a week.

The business now has three part-time employees who press T-shirts and fulfill orders, and our children still have their roles in the business. We hired an HR company to help us hire and manage the employees.

Now we're trying to grow the business without my and my husband's needing to be involved in pressing, folding, and packing orders. Our three employees do most of the manual everyday work, while my husband and I focus on marketing and content creation.

Being consistent has been the key to growing our business. Our revenue took a hit when Facebook ads became less effective with Apple's introduction of privacy features in iOS 14. But we kept showing up and promoting the brand. In recent months we've made $50,000 in revenue on average.

We believe in our brand and are now seeing the rewards as sales come in and we get closer to our dream of making our full-time income from this business.