a few very simple things (in words anyways 
)
1) Lift weights (either at gym, or home if you have a good setup) and make sure you are always pushing yourself. So increase the weight by the minimum amount whenever you are capable of doing 3 sets of 6-8 reps. Rest 1-3 min between each set. Also, you should probably do a Upper, Lower, off, Upper, Lower, off, off schedule. (or something very similar) You definitely don't want to skip your days off as it gives your body time to heal and grow. (you can throw abs in with lower body, or upper, take your pick)
2) Eat a high protein diet (2g of protein for every lb of body weight) and aim to gain 1lb/week. at least half will be fat, and the rest muscle. So you'll want to eat about 500 calories more in a day then your body actually needs. The only easy way to figure this out is to count your calories and then weigh yourself every week and adjust your food intake accordingly.
3) Once you've gained as much fat as you are willing, switch to 500 calories below your daily needs and continue working out at the gym. The idea is to get rid of the fat and maintain the muscle. Just try to maintain what you were last lifting. However, you may lose some muscle, but no big deal.
4) repeat as many times as you need for a ripped body.
I'll essentially be doing all this once I lose a lot of weight. I'm trying to get down to 175 before I start trying to build muscle again. There are some other things you can do, like protein shakes and creatine, but if you don't have the money, you really don't need them.
edit: oh, and if you need a list of exercises, http://exrx.net/Lists/Directory.html , has a complete list of exercises for every muscle group. I suggest always doing the compound exercises as you hit more muscles with a single lift, which will save you time. Yes you can do tricep extensions, but you could just do bench presses and you'll end up working your triceps too. You can poke around the web for various workout routines, but you can also make your own. Just make sure you hit every major muscle while doing each region of your body.
