An annual survey of prom spending by VISA finds teens will spend a staggering amount of money on those so-called "Prom-Posals," elaborate ways to ask a sweetheart to the big dance. The average cost - $324. That’s more than a third of what American teens plan to spend on the prom this Spring – $919 overall, down 6-percent from last year. The biggest prom spenders – in the Northeast, where those surveyed forecast a total spend more than $1100 on average - $738 for prom night and $431 for that "Prom-Posal." The most frugal prom-goers are in the Midwest – with total spending of $733.