IC,
First, I think you need to actually sit down and create your budget. Here's another thread where someone created a fairly good one:
http://www.tfproject.org/tfp/showthread.php?t=104079
By my calculation, you should be making $46,800 at a minimum before taxes. That's assuming that neither job is seasonal and based on the post-training period of your new job (congrats on that, by the way). You need to figure out what your outstanding debts are (credit cards, student loans, etc.) and make sure you're paying those down. When you're thinking about a new car, consider buying used and remember to factor in insurance (both liability and physical damage) and other potential expenses. If you don't know, use your best guess.
As far as food goes, I always found that burritos were an easy lunch to pack, especially if you wrap them in foil. They can be prepared several days in advance, and you can either eat them cold or warm them up on the engine block of a running truck (any experienced crew guy can show you where). If burritos aren't your thing, then sandwiches and even ramen-in-a-cup are pretty cheap and easy. If you're smart about it, fruit can be fairly cheap if you use your local market's "club" card (basically tells them who you are and lets them track your purchases). There are almost always sales in the produce department.