When a single item is put up for a fixed price sale, and a member clicks on 'Buy', the buyer's Therebucks balance is checked to make sure they have enough Therebucks to make the transaction. If they do, the auction is allowed to end and the buyer is marked as the high bidder.

However, the transaction does not go through immediately. The auction is placed on a processing queue which can take up to 10 minutes to complete.

During this time, if the buyer then gives away their Therebucks, or spends Therebucks on another auction, such that by the time the first auction completes processing he no longer has the Therebucks to cover the purchase, the auction will fail with the error that the buyer did not have enough Therebucks to cover the purchase.

Your listing fee is automatically refunded by the system when this situation occurs, and you may re-list the item at your convenience.