Blue, I shoot a Nikon D40. Some people say it is ole shite (quite frankly, it is,compared to the D3100) However, because it has an electronic shutter, my flash synch is 1/500 (better) instead of 1/200 with more recent cameras, which gives me better daylight shots. I like nikon because I only want/ need the three lens I have (which cover 18-200mm, plus low light applications), which were made for the smaller sensor D40. Many older series professional Nikon lenses will not autofocus or meter on this body, because nikon removed the ability to support legacy lenses from their cheaper cameras (The older cameras had a mechanical linkage to focus those lens, the new ones focus electronically with a motor). If you want to use these older lens on a Nikon, you need to buy the more expensive crop sensor bodies, like theD7000, D300s/x or go full frame D700 (The D90 manual says they are compatible, but nikon lied.). Only the newer professional lenses will work on the D40/D3100/ D5000 etc.
ALL canon EF lenses and EF-s lenses will work on ALL of their crop sensor bodies, so you can pretty much use ANY modern canon lens with the T2i option.
Since price is your concern, I am guessing you will never be shooting a professional lens on your camera (neither have I) and be using Nikon. Just buy a set of DX pluss an external flash, and you are set. Here is my gear list for you to see the stuff you might really need furthur down the road after you get comfy with your kit lens:
1) Camera body
2) Kit lens
3) 35mm f/1.8 $200USD
4) 55-200mm $200USD
5) Flash. I use the SB400
6) Tripod (Cost me 200TT by courts)
7) Spare battery

52mm circular polarizing filter (buy the best that you can afford)
9) Camera Strap (Nikon don't pay me to adveritise and it is too short for me)
10) Camera bag (dont store your gear in the bag, it will get fungus. Just use it for transport/ hiking)
11) Grey card
12) 42" reflector.
13) Bulb blower
14) Lens pen.
15) Memory cards
Hope this helps.