Don't forget the public library for a great collection of exercise videos/DVDs. If you don't find what you want, find the reference desk and ask. (Yes, I'm a librarian! How could you tell?

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I don't belong to a gym and I've lost 80 pounds so far. Granted, I have access to exercise equipment at my sister's house, but nothing burns calories like a good run outside. It sucks and I hate it, but it works! Of course you have to work up to running (I'm still working on it three years in), so you put on your shoes and go for a walk. When that gets easy, walk faster.
My point is that everyone here is right; you can get a great workout without ever seeing the inside of a gym. It doesn't have to cost a dime, and it really will help keep your weight loss going.
My motivation to keep working out, even on the days I don't feel like it, is my muscle tone. It's still covered in fat, but I can feel the changes and they are kind of amazing. It's fun, poking around at new muscles!