Trex will be way over your head price-wise. You might look at the [link=http://www.rc-tek.com/us_store/rc-tek-phantom-450-xl-c35.html]RC-Tek Phantom[/link]. The kit is only like $207 with motor esc bec and battery, then +100-180 for a gyro, +20-100 for 3 cyclic servos, + 20-100 for a receiver. So you could do it at minimum of $350ish, but your electronics would suffer, and your skills will progress slower b/c of it. I'd suggest waiting till you have enough cash to afford the high end of my estimates, at $500-600 depending on your receiver. This is all assuming you already have a transmitter, if not add another $200-300.

I'd suggest you buy all of your components for a total of about $480, then buy the DX7 transmitter, which is $320, for a total of $800. This is a GREAT entry price considering what you're getting. If you bought a trex as an entry flyer without a transmitter, you could easily end up spending $1000+.