Cheapest thing that'll run logic studio 8?

Hi there. Basically I really want logic studio 8, and therfore am forced to buy some sort of mac. However I have come to find macs are a lot more than I expected.

Bearing in mind, this is the only reason I need a mac, can anyone suggest the cheapest possible way I can have a system which will be able to run logic studio 8 to a fairly decent standard. Any help would be much appreciated. ;D

Thanks. Do you know if any of the older model macs (desktop or laptop) would be able to run it, and which ones?