One route you might take is to concentrate your funds on the mechanical hardware to begin with, build a solid frame and use appropriate motors and drivers as jazz suggests, but get started using a cheap controller using Linuxcnc on an old windows XP era compute with a parallel port if you can find one gathering dust and a cheap breakout board. This arangement is cheap enough to consider it expendable and you will be able to test your machine while choosing your preferred controller and saving up the cash.

Linuxcnc can be a bit daunting if you want to add bells and whistles but for a vanilla set-up it's very easy to get going using the included wizards.