The 9505 is the international version, and will be pricier. Different bands, which won't matter on straight talk, but would on real AT&T or T-Mobile as it's missing AWS (for T-Mobile, HSPA+ or LTE depending on the area) and the 700mhz LTE band (for LTE on AT&T).

Full price at a T-mobile store is $629, plus a minimum-cost rate plan for a month ($50 from T-Mobile, $30 if you can get an activation kit at Wal-Mart.) Should be no SIM card charge on a prepaid plan. May be able to get an unlock code right there if you can schmooze about international travel coming up. Can also skip the latter entirely if you have ANY local friend who has T-Mobile who can go in to buy it with you. I'd offer, if you were local to the Bay Area.

Might also look for an independent shop, who will typically sell an unactivated phone for full retail. Best Buy's web site also shows an unactivated price of $749, although you should be able to do better.

$719 unlocked 9500 (non-LTE) on NewEgg, after coupon: http://promotions.newegg.com/Samsung...%2f269x120.jpg