I'll try most crafts once. I bought an embroidery hoop (I only used the inside hoop), plastic rings...I have no idea what their purpose is, but the craft store had them near the yarn. I got some string from the jewelry dept (I figured if it was sturdy enough to wear, it could hang this mobile up). I found some unfinished wood trees online by searching. They only cost about 5 dollars for 10, BUT....the shipping was also five dollars. Oh well. I also got three colors of stain (which I had around my house): Cherry, Walnut, and Oak.
I drilled four holes and then doubled up more string and tied those through and up towards the ring at the top.
The hardest part of the project was trying to get a shot as the mobile swung in the wind....it's really not crooked, but...you take what you can get. I put it all together for 16 dollars, and that's including the 5 for shipping I could have skipped if I had time to hunt down those trees at a nearby store.