You pitch the idea of scracth-off lottery tickets, which is perhaps not as exciting, but has a similar potential payout with the benefit of being completely legal and safe, even if chances are proportionately slimmer. Janice picks a one dollar ticket named "Crazy Aces" and wins two dollars back. Tom spends five on his ticket and wins nothing. You're not satisfied with either outcome, however, and are still deciding even after they have finished theirs. Finally the clerk says, "Look, I can tell you want something special. Well, I think I have the thing for you."
"Oh, yeah?" you ask doubtfully.
The man pulls a single ragged scratch-off ticket from behind the counter and lays it down. In faded bubble letters it reads "HAUNTED LOTTO $2" You think for a moment but finally purchase it.
"Reveal three occult symbols to trade your immortal soul for one wish," you read aloud as you scratch off one occult symbol, then a second, and a third. "Oh, cool," you say, "I won. Now I guess I just need to make a wish."