You don't always win anything...
On the specifics of the system:BetCoin Dice operates with zero confirmations, meaning the time it takes for you to send a transaction and receive your winnings is near-instant. Bets are evaluated as soon as the client picks up the broadcast. This is safe because it always builds the answering transaction with the output of your bet transaction. This means a blockchain that does not contain your bet cannot contain the site's answer.
You place a bet by sending bitcoins to one of the addresses listed in the bet options table. BetCoin Dice sees this, evaluates win or lose and generates a return transaction. If you lose, the return is a consolation fee equaling your bet times 0.005. That means a number way lower than your bet. If you win, your bet is multiplied by the prize multiplier and that amount is sent back.
There is thus an answering transaction for each bet and normally you see that transaction in your client after a few seconds.
