It really does depend on how well you know the people and how much "free cash" you have to contribute. What you earn is obviously a big factor. When we were married we had a mixture of what people gave - ranging from $50 to $300 (from closer friends - who have well paying jobs). To aquaintances we've given $50 and to very good friends/family we've given $300 - but it's totally individual. Trust me, no one will judge you on how much you give - you can't look a gift horse in the mouth!

Good luck controlling your younglings! (What a fun day it'll be for you! )