How can you buy a 500000 home with one dollar?

This would be very difficult, and it would be impossible to do directly. You would have to keep trading up. A man did manage to buy a home with a paperclip, but it took lots of bartering. The key is finding people who need whatever you have and are willing to trade at a loss to themselves because they want whatever bad enough. So keep trying to trade up and then go look for a foreclosed home of the desired value.