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I have found Craigslist to be good for iMac G3 and G4, but anything else people seem to expect WAY to much for. In my area Power Mac G4 and G5 systems routinely are posted for well over $100, the same goes for iBook, but iMac G3's can be had for a few bucks.

Sadly in my Craigslist area the going price for a G3 iMac is $40-60. $40 w/o discs, $60 with.
 
My mini was bought for WAYYY to much. $96. I regret it, but it was my first mini. I wanted to use it more than my 1.6GHz iMac just because of noise.

The Computer Ops class has Optiplex 780 machines with Core 2 Quads to make spreadsheets and word documents. SUPER overkill for that. They could live with about anything that could run Excel and Word. I'd rather see Power Mac G5s in there than the 780s.

The 780s were in the graphics designing class and we replaced them this summer with 27 new iMacs. I was in charge of setting that all up and ML's Server setup was a nightmare.
 
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