But: most other online retailers (or e-tailers as they'd have it here; yick) won't take 'em. Usually, buried deep in the small print is something along the lines of "we cannot process cards issued or billed outside the United States".
Annoying, because the printer I want is $200 at amazon.com and most other places, but only $150 at buy.com. I want to use 'em, but they're one of the small-printers. I've tried ordering anyway to see what happens, but I think they're onto me; I shall plead ignorance and see what happens.
I'm not sure how easy it's going to be to establish credit in the US; my gut feeling is "not very". The hard-slog route is to start at the bottom with a secured credit card (i.e., you deposit $1000 or so into it so that you're spending your own money, not the lenders') and then work up through store credit, auto loans and so on. It all sounds like a lot of bother...