"One thing that is not obvious at the outset is what would motivate Amazon to keep the price down." Seems like the opposite: Amazon wants the price to be high. But they would rather get paid *SOMETHING* than have the boxes sit idle. Thus, you get to run at one cent per hour, unless someone else is willing to pay two cents (and so on). I'll bet they don't terminate *ALL* the boxes when a higher bid comes in. They terminate only enough to run the higher bidders as they come in. One big unknown: If the price changes minute by minute, you could have several people startup and get immediately terminated on the same box. In this case, Amazon would collect full-hour fees from each user in a single hour! Hopefully Amazon doesn't do this and/or has a good algorithim for selecting which box to terminate. Also, having a maximum price (8 or 10 cents an hour) seems like a bad thing for Amazon, but a really good thing for customers.