Most have access to eBay though, and look at this:
Appropriately priced Demon's Souls copies everywhere!
Seriously, pretty much any online retailer should be carrying the game for either below, or just above $20 USD. Of course most brick and mortar shops won't be stocking it anymore though. Like nearly any other title that is over three years old, a store is unlikely to be carrying it unless there is a demand for it at the time (like when Dark Souls came out, Demon's Souls was everywhere, used and new). Regardless, as far as I'm aware, PS3 games are region free, so really, anybody that wanted the game at a reasonable price previously should have easily been able to find it. It's really not a hard game to get your hands on at all.