Building models regardless of what you are building will cost you much more than it did some 5-10 years ago. Being a modeler, I know when I need material for my project, I need it and the cost for one/two prices on brass, plastic, metal is the least of my worries. I will say that since I have been modeling for some 60 plus years, I have a very good supply of these items in stock, in most cases if I need one piece, I buy two, or three, my extra supply looks like a hobby shop. As far as where I get my stuff from is where I find it and who can get it to me the fastest. I’ve even been known to stop and look at something that people put out for trash pickup, you will be surprised what scrap metal and plastic is discarded that and how it can be reused to model something else.