It only works out if you HAVE to pay by money order. Let's say you need to buy a $20 money order. The post office wants $20 for the value of the money order and then something like $3.50 more (depends which kind of money order, tho) for the cost of the money order itself. They'll let you charge that $3.50 or whatever service charge to a credit card, but they'll only accept cash or a cashier's check for the value of the money order itself. Not just because it costs them 2 to 3% to take a credit card (and thus why in the world would they want to take one on something they don't make a single bit of profit on? -- the only profit is in the service charge), but because if you paid them with a stolen credit card then the minute you walked out of the post office you could cash the money order and they'd be out the whole value. So two great reasons (from THEIR persepective) why it'd be insane for them to take credit cards.

(I notice else in this thread claims at his post office they do. Either that poster is fibbing or confused, or they've stumbled onto a post office where the postal worker doesn't know the rules or else is knowingly violating them.)