Many yoga and fitness studios have at least one donation/community class per week that is heavily discounted. I’m not sure what the cost would be in NYC, but in my mid-size Canadian city, it’s a minimum $10 donation, which is around half the cost of a regular class.

If you have 4–5 hours a week to spare, many yoga studios also offer “exchange” programs wherein you do some light cleaning and/or reception work and get unlimited classes. Some even have agreements with other fitness studios that allow you to take free classes there as well. It’s a great way to stay fit and save a ton of money.