It was super easy and relatively inexpensive considering how long they will last. Here's what I used:
2" binder rings
Paper Key Tags
5 Second Fix
I simply wrote the number on the paper key tag with a Sharpie, I chose to take the ring off the tag and simply put the tag right on the number ring. You could definitely leave the key ring on though. I then put the number of beads on the binder ring that corresponded with the number written on the tag and closed the binder ring. I didn't want the rings to open while they're being used so I used 5 second fix to solve that problem! If you've never heard of this stuff see my post about it here. It's AMAZING!!!
And here's the finished product!