My three piece band charges pubs about £250, parties £300-600 and weddings £600+. There are only three of us, so the split's a lot better. I think you need to be competitive to start with but not to the point where you're only clearing a few quid. Also, factor in the cost of lights and extra kit you'll have to buy to do those sorts of functions. Pass that on. I think it's also good point to break the cost down for people so they understand how many hours are involved. People don't really understand the cost of a band, so it's helpful to explain.