I haven’t gotten to the point of actually needing/using a capo, but I wanted to be ready. So I found a cheap capo on Amazon for just $2.50 with free shipping. It came straight from China, so it took a couple of weeks to get here. But outside of the spring being a little heavy, it’s well made.
I also found a post on how to make a quick and cheap fifth string capo out of a ball point pen cap. It seems to work pretty well.

I’ve also been looking for a good mute so that I could practice without bothering my family–especially since the “music room” (our spare bedroom) is almost directly below my son’s bedroom, and my banjo can be heard pretty clearly from upstairs.
I was thinking about getting a Mike’s Banjo Mute, as they come highly recommended. But while $35 for one is worth it, I thought I might be able to find/make one for less. While thinking about this problem, I started playing around with my banjo and the capo. In a bit of inspiration, I slid the capo sideways onto the bridge until it pinched the bridge in the middle. It is impressively effective! It barely clears the strings, so it doesn’t knock the banjo out of tune or get in the way of my picking hand. The only problem is that besides quieting the banjo, it gives it a muffled sound. I can’t help but thinking that it makes the banjo sound like it has a cold…

PS. You might also notice some white marks on the side of the neck in the shot of the fifth string capo. The only complaint I have about my banjo is that they didn’t put side marker dots on it. So I used some Wite-Out to mark it temporarily. I haven’t decided whether to do something permanent or not.