Meinl CFT5-BK Cajon Foot Tambourine

I don't play cajon, but I do play guitar in situations where a little live percussion goes a long way. Attached to your foot, it readily produces an effect roughly like a hi-hat. You can also attach it to your shin or elbow, or just hold it in your hand if you have one free.

You can get about the same variety of sounds from it as from a regular tambourine, e.g. slap, shimmer, tap a single jingle with a mallet/finger, etc. It also gives an egg-shaker like sound if you operate it perpendicular to the usual up & down direction.

It only takes a couple of seconds to slip it on or off your foot. You will probably be able to feel the hook-and-loop strap under your shoe, but unless you're doing a lot of walking with it on, this shouldn't be a bother.

OK, it's probably not the best quality tambourine in the world, but it's not the most expensive either, and for most purposes I'd say it should be decent enough. The sounds are good, the foot attachment works well, and I can't see it falling apart without some abuse.