50th Wedding Anniversary For Parents

Help...My brother and I would like to have a party for our parents 50th Anniversary. We have rented a hall and have around 50 people we would like to invite. The cost of doing a buffet dinner and drinks is more than we can handle. We were wondering if anyone had any ideas for a short evening party , say for about 3 hours that included drinks and appetizers or finger foods. We are trying to keep the cost down but do not want to appear cheap. Any ideas would be greatly appreciated. THANKS!