It seems there are two different questions. One is whether or not our prizes are decided at the spinning wheel. As most here believe, our prizes apparently are not decided at the spinning wheel. The reason is that sometimes we can know the prize before the wheel is done with the spinning.
The other question is how our prizes are determined. I don’t think the prizes themselves are predetermined. It may be, but it seems too complicated. It makes more sense to have a program that distributes probabilities to the prizes and then run on those sets of probabilities. This is simpler and actually explain our experience (mine, at least) with prize distribution. And also, this way it wont matter if you take into consideration the plays of one player or the plays of all players: the probabilities of getting a certain prize are going to be precisely the same. So, normally we get either coins or food because the probability assigned to these are higher than those assigned to anything else. As it was mentioned before, we don’t know exactly which probability is being assigned to each prize. In a normal lottery, for instance, we do know that. In fact, we don’t even know if the probabilities remain the same for a prize that just came out – if the program lowers the probability for a prize that just came out, in order to avoid repeating the same prize, it would make things very different from flipping a coin.
Anyway, If that is how things work, one thing we learn is that we will increase our chances to win improbable prizes playing more times. Of course, improbable things can happen anytime, but if we play more, more chances we have to get those infrequent prizes.
One final thing. In order to avoid frustration, we should adjust our expectations toward the prizes. I don’t think 500 DB, for example, is “decent.” This is one of the best prizes we can get and I’m pretty sure one of the most improbable.