I've been reading this thread with great interest because I have 3 weddings to go to within a month. I've often wondered what is an appropriate amount to give for going to a wedding. For those of you who expect large checks from everyone, let me ask you this...What about the close friend you invite who doesn't have that kind of money? Do you not invite them because they will not give enough? Or do you simply make an exception in your mind that their $15 is 'okay'? I am so poor that for me, just going the wedding is practically the only gift I can give. Two are nearby, one is a $260 plane ticket away. I will probably give a card and a $20 gift-card to each couple. I can do no more. Thankfully, my friends know my situation. Even more thankfully, they aren't snobs who expect some certain amount from me for admission.
If you want to demand a cover charge for your wedding, then do so. If you want to invite your friends/family to celebrate your marriage, then do so with a right mind...No one owes you anything. Every single gift/card/whatever you receive, is a gift of grace...you don't deserve it at all. If you expect some certain gift value from each person, your greedy self will be sorely disappointed.