I had the same problem because I work in IT and winter is not good for working outside. So I went and bought a stationary bike and a treadmill. Now you might be thinking that those things are expensive and you said you had to dig deep to come up with the 30 bucks for the gym right. So i looked at craigslist in your area and I see plenty of people trying to get rid of stationary bikes and treadmills for cheap. For instance this guy was trying to get rid of three things for 50 bucks.
http://cleveland.craigslist.org/hab/1498248219.html
So you get the idea about looking for used equipment. For me the stationary bike is a wonderful form of excercise and it seems someone is always looking at getting rid of the for cheap. I know there are always people who want to dump their old excercise equipment that is still in good condition.
Here is an example
http://cleveland.craigslist.org/hab/1498248219.html
So i think you may be able to find cheap excercise equipment if you look
take care