We loved this budget framing idea from local writer and AT:SF reader Anh-Minh.
She and her husband (this is a team project) used very large pieces of Plexiglas to sandwich an array of sepia photos, then wall-mounted them using six pre-drilled holes. The resulting panoply is dense with visual interest but also really dramatic at a distance.
Anh-Minh's idea is a relatively inexpensive way to preserve and display large art as well; a good solution for posters and giant photo blowups. It also has the benefit of flexibility. Unlike art in most types of large frames, it's not impossible to change the image(s) in your plexi wall sandwich.