Small used unicycle wanted

I am interested in find a small unicycle for my children. My boys are 5 and 7
and at least the 5 year old would love to learn to ride.

Anybody know where I can get a used 16" unicycle? I am guessing that a 16" would
be the right size. They both can just fit on a 20" bike and are about 48" tall.

It seems a shame to spend money on a new one when I don’t know if the kids
will every learn to ride it and they will probably outgrow it in only a
couple of years.

Andy Arhelger Rochester, MN