I'm not much of a ring person because I always play with them and then end up losing them really quickly. So it's hard for me to justify buying rings or spending much time making them. But this DIY is pretty perfect because it requires basically no supplies/money and was so easy that if I lose it (I will) I can just make a new one in a few minutes. Here goes.
Take a strand of jewelry wire and wrap it around the part of your finger you want it to cover (I made an upper-knuckle ring here, but you can just as easily make a regular one). Cut off a strand that fits around your finger at least four times. Cut two more strands of the same length. Tape an end of each strand to a table or other stable surface. Then braid the three strands together. When the braid gets long enough to wrap around your finger, cut the wire to size, making sure to hold the end so the braid stays put. Use a large clasp piece to fit the two ends of the ring together. That's it! I'm probably going to make several of these to prepare for the inevitable losses that will occur.