Just an idea...
If you cap the raffle at 100 tix, you could assign a two digit number to the buyer in the order tix were purchased (00-99). After all 100 are sold, wait 7 days after #99 was sold, then just pick a State's daily 3 digit lottery number and match the last two digits.
If you use New York's, you'll have to specify the midday or evening number. We have so many gamblers here, the "daily number" is actually "semi-daily".
New York Lottery Results
I think that would be about as random as could be expected. I'd go in for one. I'd vote for $20, it will be a lot of administration/capitalization for a paltry 1G.
Jack
P.S. You could even give a buyer
ONE request at which number he prefers. If this one number is previously assigned, buyer defaults to lowest unassigned number.
P.P.S. Save #15 for me if this is how it ends up. I will pay instantly with Paypal. Maybe you could even start a new thread with number requests and then fastest clickers/payers get their number.