If you have a tight budget—and plenty of us do—there are fitness facilities like the YMCA that offer financial assistance programs. There are also many programs in the USA offering free fitness classes. I highly recommend researching online for these as many people are not aware that these programs even exist in their area. If you live in or near NYC you check out programs like shape up. https://www.nycgovparks.org/pr
ograms/recreation/shape-up-nyc . Also many fitness apparel stores such as Athleta offer free classes as part of their community outreach programs.
Get creative. For example, when I was struggling with money, I made my own medicine balls. You can purchase a regular ball from a dollar store and fill it with sand. You can even add weight to exercises like lunges by filling a backpack up with weighted items. I used to put phone books and text books in a backpack and do some leg work that way.
If weather is warm in your area then you can of course do cardio like jogging or running stairs outside. Make use of whatever you have available in your area. Park benches and chairs can be used for step ups, tricep dips, Bulgarian split squats, decline push-ups and the list goes on. Don’t let lack of financial funds get in the way of achieving your goals.