It's nice to win a prize but, the prize doesn't need to be worth a million bucks either. If you can find a way to do both that is ideal!
I know at the larger barrel race events that we've been to, they have prizes that are decent but the added money is truely what draws the crowd.
At our series we offer prizes to 4th place with Troy Fischer buckles to first. He is very reasonable and it is easy to find sponsors that win donate $350 rather than trying to find ones that will sponsor major prizes such as saddles which will cost anywhere from $1200-$4000 depending on what you want.
IMO: Try to find "decent" prizes but I would consentrate on the added cash....