I've used these in the past, and are slightly cheaper than the first one:
http://amzn.to/2CsSwi0But as btc-haze pointed out - it's hard to beat eBay and picking up used ones on there. The only thing I would want you about is if you're getting a smart PDU with power cycling, etc - I picked up a bunch of Tripp-Lite ones a while back so I could do remote rebooting when needed, and the stupid things only have a relay on one leg of the power. Net result is that with some of the better server power supplies will continue to operate even if one leg goes down.