Need advice on graduation parties.?

Ok....I need help resolving an arguement. My husband is a high school teacher who is very well like by his students. This year he is bombarded by graduation invitations. In the past he had made it a rule not to go to them because he always felt bad that he couldn't make them all and didnt' want to single out anyone and have hurt feelings. Now he really wants to go to some but we can't afford to give money to every party we go to. He feels bad if he doesn't walk in with a card with money. I told him that he should just go to make an appearance, meet the family, give congrats and leave without eating. What do you think! I just don't have the money to shell out to people I dont' know and really can't afford it.