I just started figuring all this out a week ago and am still putting together the pieces. The easiest way to put a rig together without spending crazy amounts of money is to-

1. Raspberry Pi ($70)
2. USB Hub ($10-$20)
3. USB powered fan ($10)
4. ASIC miners, I ordered 2 Gekkoscience 2Pacs ($80ish each) but as far as I know you can get more so long as the USB hub can support them

I won't make much of anything with that setup, but I'm doing it more as a science project than anything... The good thing is the skills learned can be applied to future ventures.

Setup is pretty simple and there are tons of videos on youtube of how to set everything up. Currently, I have everything configured and cgminer (one of the programs used to mine) loaded up. Just need the 2pacs to finish up. There are support threads on here for the 2pacs and cgminer where research can be done and questions directed.

I'm not sure how good you are with computers in general, but even if you are somewhat savvy plan to spend multiple hours learning about everything.

Hope that answers at least some of your questions.