Do you have a very talented group of friends and relatives? Don't be afraid to ask them to get involved in your wedding plans. Some may volunteer and offer their services as a wedding gift.
If you like what's being offered, go ahead and accept, but make sure you know exactly what you're getting and they know exactly what they're doing.
While you may not want to write a formal contract between friends, you want to know that they won't cancel at the last minute for a paying job or a conflict, leaving you without a key wedding element. Just to be safe, check in with them every now and then to confirm that they are still prepared to deliver the goods or services on your wedding day. And if you get the feeling that something's wrong, don't be afraid to ask if there's a problem and if necessary cancel on them and hire a professional or buy the items yourself.