Money is always a great prize, so I'm happy to see the $200. How many places are you thinking about awarding? If you can afford it, smaller money prizes will always do, even if its a small amount.

After all, unless you've made something yourself that you can't get anywhere else, like your own game, then money is the best thing. Unless you are willing to purchase something with the money, like a programming book or a piece of software, and offer that as a prize, though money is probably the easiest, since winners can than spend it on anything they want. With no contest sponsors, it would be hard to award any other kind of valuable prize.