If this is the lens I was looking at earlier today I suspect all that is wrong is oil on the blades that have locked it up. Oil from the helicoid will over time outgas and deposit on the blades making them sluggish and after sitting up for long periods of time will not move..

This is an easy fix for a repairman.

If it goes over $375 I'd forget it since the added cost of a CLA would push it over real value..