I need to cut the legs shorter on my
chairs. No one sells a chair saw. What should I buy for this?

No saw needed. Simply take the chairs outside and put them on your
driveway. Take two bags of concrete and stack them on the chair seats
and drag them up and down the driveway until they are the desired
height.

Alternately, you can chew the legs off while watching TV. Make sure
you mark your chew line though, so you will know when to stop.

You can't just run out a buy a tool every time you have a new project.

Robert