I called my friend in New York for about 10 mins from Disneyland...OMG $50 when i got home. I was about 15 then, and damn that was a lot of money!
Also, a freind of mine got charged $300 for his internet-phone line. The internet provider said the number was local, but the phone company had signed him up for long distance, and the "local" number wasn't. He called the provider and got them to DC service, and left it all for MCI to pick up, since he'd never asked to have long distance, and should never have had that connect in the first place.