Went to IKEA and got some frames for my posters. It’s the Marietorp frame, which was pretty much the cheapest poster frame I could find from there. It’s not of the best quality, but it works just fine.
Trying to put my posters in straight was an exercise in hell, and I’m still quite sure some of them are a little crooked inside. My dad helped me mount them, and they look much better than without frames. That, and the Blue-tack was just useless at holding the posters up.