ibook or powerbook for semi hardcore image editing?

hello all, im new to this forum and on macs as well. im just a college student and very tight on budget and I've been thinking about getting either a used 12" g4 ibook or powerbook (both at least 1ghz) for heavy photoshop and illustartor work (preferably cs2) my questions are: which one should i get? is ebay a good place to get one? also, I noticed that 867mhz powerbooks are pretty cheap but is it good enough to do work on?

thanks in advance!