As far as I can tell a single person can't win the same raffle twice. The other assumption I made is that everyone will have 10 tickets.
Henceforth, 10 tickets / 120 total tickets, somebody wins that's not you, 10 tickets out of / 110 tickets, etc. So in short, 1/12+1/11+1/10. I stand by my ~25% chance until I see somebody win two raffle awards some week.
EDIT: If you really want to complain about something mathematic, point out that 1/12+1/11+1/10 is not actually 25%. Which would be very true. But I never said it was exactly that~