They can probably be repaired, but if they are C lenses it may depend on what exactly is wrong, as new parts are not available.
As for cost, a CLA will probably run about the same as a working, but otherwise random condition replacement. But probably less than a newer lens in good or excellent condition (assuming these are C series lenses).
I would probably go for the repair, or at least an evaluation from a repair shop.
Hope that helps.
(I guess you'll be doing a lot of wide angle shots for a while
)