Can you tell us a little more about your rig? Year/model/engine

It definately sounds like the slave to me. Mine went out on my commuter a few years ago. I have a feeling the Hilux will give up the ghost pretty soon.
Using my '83 Hilux as an example, a rebuild kit including the piston costs $17 at AutoZone. A new cylinder is $30. It's far easier to replace the cylinder than rebuilding it.
If your rig is newer, it may cost more. But that will put you in the ballpark.