Legit raffles - help

Hey, I would like to create raffles and make people completing surveys\content lockers for them. I want to do it legit, meaning I will ACTUALLY select a winner randomly and provide the prize money.

Any good CPA network that allows this type? Of course that people will know that it's a raffle, and they CAN win but not FOR SURE, so they won't be able to complain.

Is something like this viable? Any suggestions?