Video: Suspension trainers give you the flexibility to do a solid bodyweight workout wherever you want: At home, at the park or under a tree. The entire thing is just a set of straps with handles that you can attach to a door, a tree or a pull-up bar. For about $US10 ($13) and a bit of your time, you can make your own suspension trainers at home.
The tutorial for this minimalist DIY suspension trainer comes from Ben Gait. You need at least 8m of polyester webbing that's bought in any hardware store. (The video's commenters have recommended having 30 to 60cm extra.) A package of ratchet tie-downs can also work. For the handles, you need about 30cm of thin PVC pipes (just wide enough for you to grip comfortably).
Gait's suspension trainer distinguishes itself from other similar DIY trainers by being extra lightweight and baking in adjustable straps. Even with properly manufactured ones, both straps on a suspension trainer should move freely to adapt to your exercise, yet have a sort of built-in safety mechanism in place to prevent slippage. These suspension trainers have those features, so check the video for step by step instructions.