Frames usually (but not always) come with aesethically matched mats; might be OK for small galleries, but ditch the cheap, impure glass and invest in UV-retardant glass (often specified for gallery-exhibited prints e.g. Ilfochromes). IKEA frames have often less than precise mitres and flimsy glass. If the gallery you are exhibiting has particular presentation standards, follow those standards e.g. consistent framing right across the image range. A framer is the best friend you can have when preparing an exhibition, even though the DIY temptation can be overpowering.

Museum-grade conservation framing is never, ever cheap: I average $195 each 460x305mm print, or $130 for a 20x20cm pinhole print. Wouldn't think of doing it myself for risk of stuffing up the matt or framing!