If you need someone to actually purchase it for you (because of restrictions i.e. store accepts US credit cards/paypal only), use PriceUSA. If you just need to ship it somewhere in the US, Shipito is definitely the way to go (it will almost always be cheaper than PriceUSA for simple mail forwarding). Especially for multiple packages as they have cheap consolidation. Shipito also has a very cheap shipito airmail option which is good for smaller things (although it takes a month or so to arrive).