If the work is done as part of the annual/100 hour inspection the cost shouldn't be great.
My plane just went in for a 100 hourly inspection and the LAME pressed to replace the control cables, so I guess they are on the look out for this area. Maybe the recent Beechcraft reports of corroded control cables were the catalyst for this interest.
I got quoted $200 for new cables, so it's not a big deal.
I find it's a good idea to follow the LAME's suggestions, and the cost if not great anyway,