+1 for eBay.
You can do a search for "MacBook Pro" and set a price limit so then you can view all the MacBooks in your price range. For example, [redacted] looks ok.
If you're patient, you could try bidding on various MacBooks, you can
sometimes get a good deal that way, but be careful you don't get sucked into bidding more than your budget which happens quite easily when you find one you really want. It can take a while, but you could get a good MacBook for a lower price than it's worth.
Good luck with your search
