You can build this cat toy for ~$5 from parts available at your local hardware store. The toy dangles a target of your choosing from a length of wire, attached via an alligator clip; if your cat gets bored you can unclip the target and replace it with something new.
Here’s a short video, followed by instructions to build your own:
Note: in this video I’m using a plush mouse for a target, which increases the total cost of the toy, but the last few seconds shows the toy with a cheaper target attached: a grocery store receipt.
Disclaimer: This toy uses metal parts, build and use this toy entirely at your own risk and play safely.
(2) 36″ Lengths of ‘Music Wire’ (1.57 mm thick)
(3) Aluminum Cable Ferrules (1/16″)
Check to make sure the tip of your music wire fits through the cable ferrules.
(1) Alligator Clip (1.25”)
Check to make sure your clips have holes on one side (as shown above). Also make sure the tip of your music wire fits through these holes.
(1) Needle nose plier
(1) Hard surface for gentle pounding (like a cement block or sidewalk)
On your hard surface, lay down a length of music wire and cover one end with a cable ferrule.
To cover the wire’s sharp tip, keep the end of the wire inside the ferrule, just short of flush with the ferrule’s end:
With the ferrule in position, use a hammer to gently pound the ferrule shut:
After pounding the ferrule shut, take the remaining bare end of the wire, and thread it through the hole on your alligator clip. Make sure the side of the clip with the hole is facing down towards the ferrule on the end of the wire:
Release the clip and let it slide to the end of the wire, stopping at the ferrule:
Using a pair of needle nose pliers, crimp the longer end of the clip around the music wire. This will bend and form the clip closer to the music wire and reduce sharp edges.
With the alligator clip threaded and crimped on the wire, again lay the wire down on your hard surface, and fetch a second length of wire along with a second cable ferrule.
Join the two lengths of wire with the second cable ferrule, again recessing the tips of the wires inside the ferrule, and gently hammer the ferrule shut.
Position and hammer a final cable ferrule to the remaining bare end of wire (this last ferrule just covers the sharp tip of the wire).
Have fun attaching various targets to the clip and playing with your cat!