Unfortunately right now there aren't too many decent deals going on for new systems. But if you want, you could check out the Amazon Warehouse Deals thread and keep an eye out for a PS3 or game/console bundle. Most are just customer returns from people who received the item and just didn't want it once they received it, so the system may not even have been used.
I got the Black Friday bundle with Pixeljunk Shooter/Uncharted 2/Karate Kid remake Blu-Ray for $225 shipped w/ Prime about a month or so ago. It came with a 160gb hdd(but this is moot since PS3 HDD's are user upgradable), so you won't run out of space for quite a while.
As long as the packing slip/receipt for it doesn't say USED anywhere on it you can register it with Sony as a new console and even get an extended warranty from them($45 for one year, $60 for two years).
But be warned that you WILL need a copy of your receipt from the purchase to be sent in should the PS3 ever need in-warranty service.