For the longest time one of the biggest problems I had was with prizes; what to give away and keeping prizes in stock. I generally would give away gift cards or candy because I had no other ideas and they were quick & easy grabs from the store.
However, I came to find out that students really weren't digging the prizes and we were spending a little too much on prizes. Thus how the prize trunk came to be created! Essentially the prize trunk is like a cooler version of the treasure chests that have filled dentists office for ages (side note: I apologize if your dentist office did not have a treasure chest while you were growing up. I'd like to say you didn't miss out but I'd be lying...)
Our prize trunk was found at an estate sale for $5 and as a bonus it came with a lock & keys! I fill it with all sorts of random goodies from the toy aisles among other great things like Detroit Tiger hats, Woodside Students gear, an adorable year-long calendar filled with pictures of cute pets, to name a few. One of the best places to get prizes is Five Below. They've got a ton of options that will help to fill your prize trunk up for quite a while without breaking the bank.
I've found it easier to keep prizes in stock and that students really enjoy the prize trunk because they like being able to dive in, see whats in there, and pick out their own prizes as opposed to being handed a $5 gift card to Radioshack.