Lately I have been looking at changing my phone and wanted to know a good place in the US where I could shop online and get good bargains on Android phones such as the HTC One S or the Sony Xperia Ion.
When buying from US store you must check the operating frequency band as the band use there is not used all over world
Did you tried Ebay ? It's said to have a good deals across various products.
If you're up to dealing with potentially sketchy people, Craigslist is a good place to find the occasional bargain.
Tiger Direct, NewEgg, Amazon are good places to start. I have purchased an unlocked phone from http://www.n1wireless.com with good results, though not always the newest products.