Hiya,
I use to be obese myself. Not quiet as bad as you were, but the first step is recognizing there is a problem. Some advices:
1. 95% of the road you need to go down is in the kitchen, not the gym. Nonetheless, exercise is important for other things. For a broke guy, you should look at going outside and walking. Use mapmyrun.com and come up with a 1, 2, and 3 mile course that's easy and safe, and then go do one of those distances a day.
2. Atkins. At least for a year. No alcohol. No processed sugars. You will be unrecognizable (in a good way) in 3 months. The rules are relatively easy to follow.
3. Find a buddy. Or use this forum. Something to keep you accountable, like AA has sponsors. Hell, I'd be your sponsor. Just find someone whose going to call you on the horn once a week and give you shit about eating right and doing the walks. And someone you can call when you are tempted to eat that free cookie they give away at the grocery store.