If you don't mind getting a PAL version, import it from the UK.
Try dvd.co.uk, or thehut.com.
I used thehut.com, and it came out to be about $25 or $26 USD for a new copy, including shipping.
Since there's no downloadable content, version shouldn't really matter, as long as you're playing on a HDTV. If you're playing on Standard Def on a North American PS3, the PAL version won't work.