All PoweriSers in the US come through xphub.com, who own a massive warehouse with them all in. All other sites are distributors, who people can order through, and then the distributors put in the order to the xphub warehouse, who ship them out.
Poweriser.com is owned by a distributor, and powerisers.com is owned by xphub, which explains the price discrepancies. I expect xphub charge distributors a fee, and then the distributors have their own margin on top of that to make profit. So say $100 default import price --> $230 for the dealer --> $360 for the consumer. That way, both xphub and the dealer are making $130 each on every pair sold. This is all random numbers though, I have no idea on the prices to import into the US or what xphub charge their distributors.
Why xphub are selling at $370 i'm not sure, probably to set their prices roughly the same as their distributors (and in the process gain one hell of a profit). After all, if they sold at $250, people would probably avoid them thinking they're fake or not riSers.
Or at least that's my understanding of how it works, as recently XPhub have had problems and so all distributors have been unable to put in orders or have them shipped out.
