Ok, so a few hundred. Though depending on how much you are selling single and multiple tickets for, it could very well be over 1,000.
But either way, it’s still a long shot. This thread makes it sound like this is some awesome idea to raffle off a free year in seminary. I’m just pointing out that this has nothing to do with seminary, it is a raffle with a cash value to it, other institutions raffle off “a dining room set”,”an apartment in Israel”, $25,000, $100,000… It’s all the same thing, an incentive to give tzedaka. Give it as t2daka, not because you think you will win.
If you have a class of 50 Beis Yaakov 12th graders and you raffle it off among them – that’s another story.