We are potential first time home buyers. The people we may buy from are our next door neighbors. They don't want to go through a realtor unless we do, but we don't think we do. We know the down payment has to come from us/our income, but what about closing costs? Some random calculator I found said they could be up to $15K- way too much for us.

Are there really closing costs w/o a realtor? Can they be part of our home loan?