new developer questions

hey guys,
i am going to school for computers, i am going to start programming mobile applications. i need advice on what mac to get, now i have alllllways been a pc guy, but realistically, i know that i need to have an apple to do this the right way, i.e getting things on apples app store. i want to get an older mac before i go spend over 1k on a laptop because i am still a student, what do i need in an apple to use xcode and make sure that i can get the coding done. most of what i do at first will be java, then prolly some obj c to get more speed out of the applications.

thanks