Joseph: ok, let’s go with your theory…. if you purchased a $100 ticket with Maaser money and won a $3000 prize, how much maaser do you have to give? $3000? Then what was the win? It sounds as if you are saying the investment in purchasing the ticket is Maaser money and the winnings belong to Maaser and not yourself.
If you go with the other approach (which I did ask a very competent Posek) you would deduct approximately $5 off the $100 price of the ticket as your value in the possibility of winning the raffle prize.
– My Rav’s psak is win $3000 for $5 ($95 was tzedakah)
– Your Psak is pay $0 up front ($100 is all Tzedakah) but pay $3000 to tzeddakah if you win and have no win.
Think this through and make sense of it.