its not something i really have experience of in all honesty mate. That said i have just taken an A3 size print to a local framer and am having it mounted on a backing board, framed and some non reflective glass fitted. First one i have ever had done and only doing it because i got the print for free and was overjoyed with it when it came back. That prompted me to really push the boat out and get it framed and mounted properly.

I think you could probably reduce your costs by not mounting on backing backing boards etc but again i think it will be a case of suck it and see what happens. I think using a board makes it more durable and easier to remove from a particular frame should you want to, thus reducing any potential damage to the shot through bending with fingers etc

like i said i am not overly clued up about it generally mate, so just my thoughts really

rgds
Dave