I'm also willing to bet the merchant processing fees for this kind of application are pretty darn high unless it's a magnetic stripe or fancy contactless reader (not that this is used much in the US). After all, the chargeback rate must be significantly higher with this kind of app vs. a normal CC terminal (even a rented wireless one).

If someone said, "hey, let me type in YOUR CC in my iphone" to pay for this rusty lamp, I'd tell them to take their garage sale item and shove it.

-g