For a European car they are probably the least expensive to repair. You might want to check out
www.rockauto.com and check out things like starters, etc. Everything tends to last a long time on these cars, but an 88 will probably need some work soon.
Check the engine wiring harness. Make sure the plastic covering is not coming off. They had problems with the wiring on the 80's 700 series, I'm not sure about the 240. Make sure the rack and pinion boots are good because a rebuilt rack is really expensive. Oh, and AC systems are adequate but touchy when the balance of freon is not just right on older Volvos. Fixing AC is really expensive on any car.