Weight lifting builds muscle, makes you heavier, and burns calories. Cardio builds endurance for whatever activity you're doing for cardio and burns calories. Eating more calories then you burn makes you fatter. You can get skinny lifting weights and you can get fat running.
If you just build up your arms like every kid has to do, and you ignore your core, the most important muscles in your body, you will at some point give yourself a nasty injury because you think you're strong but you're actually a weakling with big arms. Squats are the most important exercise you can do. There's a lot of good free information at the crossfit site. Check out the videos by Burgener and Rippetoe. http://www.crossfit.com/cf-info/excercise.html
All you really need is a flat bench, a squat rack, a good bar and weight set.
Btw the hi-temp bumpers are good and relatively inexpensive.
