Honestly you'd be better off buying a peel from a restaurant supply store if you are using it in your home. It will be a lot cheaper.
Spbrez, if your goal is beauty, there's really not much you can do with a peel. You don't want to sand it too fine and you definitely don't want to put a finish on it, because the pizza won't slide off as well.
If, on the other hand, your goal is thrift, I haven't priced out wood lately, but I'm sure it wouldn't be that much cheaper than your standard $18ish 18" peel. You could look into formaldehyde free plywood, but, it's hard to track down and may warp.
The other thing that many people aren't aware of is that peels aren't flat. It takes some serious equipment to get a gradual taper from end to end (40 or so inches, including the handle).
I'm a big believer in DIY, but when it comes to wood peels, I think it's a losing battle. Metal peels for WFOs... now that's another story.