how much would you pay for a Bob Bryan autographed tennis ball?

serious answers, the fact that bob has signed it doesnt add a great deal of value, its nothing personal its just that players autograph alot of balls, shirts, hats etc i couldnt imagine ud get more than $10 for it, id assume that only tennis players would know of the bryan brothers and any player who played enough would want a novak, rafa or personally a fed signature. as there freakish players who only come along every so often. srry.......:)