Bravesfan,
As goinstraigtup and minnflyer mentioned, use a Y-harness to connect 2 servos.....basically what that does is controls 2 servos on 1 channel.....4 channels = 5 servos. When you move the aileron stick, both servos will move simultaneously.
I hear ya about the budget.....I've got 2 little ones myself!
What you mentioned about getting a used radio might be a good idea (just make sure you get it from a trusty source)....then later on you can get something nicer with multiple-model memory, without laying out too much cash on a "first" radio.

Mike