Best buy or wal-mart pretty much always have the lowest prices on consoles, and they're all over the place, so I'd recommend going there. As for which console, if you're just planning on getting arcade titles, you need a hard drive, cause the games range from 40MB to around 200MB, and the memory card that comes with the arcade version is only 256 MB. I think your best bet would be the standard, 20 GB one. Anything more than that is overkill for what you'll be using it for, and the only thing lower is the arcade model, which doesn't have a hard drive and is only like 20 bucks less.
Arcade:
http://www.bestbuy.com/site/olspage....=1186006196578
One you should get:
http://www.bestbuy.com/site/olspage....=1186003685732