A friend of mine who exhibits annually has given up on framing. He'd previously spend $6k on framing, sell $4k of prints and just put up with the loss.
For his most recent exhibition, he decided to just nail the FB prints directly to the (wooden) wall with large (4") steel nails. Fitted well with the room decor and his style but it's not a mounting method that will appeal to all
$20 for the nails... and still sold about $4k of prints.