kramer - you are right - all ps3 games are region free.
Re prices, many games, if released for Asia are at the rate of about 60-75. US-released imported games usually priced between 80-95. European released (eg. PES2009) can be more expensive, but if you buy in the right place should never exceed 100 sing. (Some places, I know, sells 110-120 sing dollars for PES2009 - what a ripoff).
When I ordered from Amazon, it is taxed and GSTed. In the end almost the same as the one I can buy here, and if I buy the US import here, I can play right away

So I usually used Amazon when I go to the US (deliver to my hotel) or if a colleague visit me here...
(I hope that's legal eh??)