i have AT&T unlimited data... and if you have a jailbreak iphone theres a program called MyWi 4.0.. its a one time payment of $20.00 and turns on with a push of a button.. ive used it a lot, not to run urt, but it doesnt affect my phone bill at all.. whereas if you were to buy a tethering plan through the provider it would be like $40/mo.