A 35-year-old Brooklyn resident gave up buying new clothes. A 22-year old in San Diego swore off retail therapy at Target. A 26-year old in England banned carbonated drinks from her shopping list.

These three women, who don’t know each other, all started the year resolving to spend money only on necessary purchases, or what is popularly known as engaging in a no-buy challenge. The self-imposed rules of the challenge are simple: participants pledge to stop buying non-essential items, be they unneeded shoes, additional beauty products or other impulse buys for a set amount of time, usually 12 months.

What started several years ago as a blogged-about experiment in budgeting and mindful spending has become a popular trend on social media. A Reddit group where people share their experiences has 51,000 members. The challenge primarily gained popularity on TikTok, where some videos of users seeking to hold themselves accountable get hundreds of thousands of views.