This is how I'm currently displaying my photos, and I love it! I find people see this the most, since my kitchen & dining room are attached, so its nice to be able to display them in a way that people can look at them. At $3 per photo, you kind of want to be able to show 'em off, right? haha.
You may not want to do this if you have young kids, because they can fairly easily ruin them by bending or touching them, but you could always just so the top half!
When I was in my tiny little bedroom a few months back, I couldn't fit a headboard in my room. So I displayed my polaroids above my bed in this heart shape to add at least something to the wall. Unfortunately this was before the time of me owning a nice camera, so this is an iPhone photo. You get the idea, though!
Anyways, hope this maybe gave you some ideas of how to display your polaroids (or instagrams!). If you have a neat way of displaying your photos, please link it in the comments below - I'd love to see!