How much money are they asking? The pleo may or may not be fixable. It is possible that it is only a battery issues and a new battery will get the pleo going again, however it is almost impossible to get a new battery right now for Ugobe pleos. The egg batteries seem to have disappeared from the market at the moment.
It is also possible that this pleo is bricked and may never work. There are quite a few bricked pleos out there that have computer, power, electrical or mechanical issues or combinations of these. So unless you are a very techie person with lots of skills you may not be able to get the pleo going again if it is bricked. Also there is nowhere to get spare parts for pleos so if it has a mechanical issues that requires spare parts you are not going to be able to do the repair.
I would think very carefully before jumping into this one. You could be lucky with it just being a battery issue but you might not be.