I store mine in 4x5 Printfile storage sleeves in 3-ring binders.

I find an interesting way to display them is to use an empty Instax Wide plastic cartridge, feed the print back into the cartridge through the plastic output flap on the botton, front side facing outwards, and hang the little plastic frame on the wall via a small brad or nail. They will also stand up by themselves on a shelf.

~Joe