Touch the wheels after some stop and go and see whether there is a difference. The hotter one has the problem, i.e not releasing properly. Should be the left front.
It is normally recommended to replace both calipers together. I would also replace the rubber hoses (with braided stainless steel) if you keep the car for long term.
17 year old cars will have some need for parts, unless the previous owner has replaced already everything, but then he wouldn't be selling...That's why the inspection is so important before you buy.
Good luck
Reinhard Kreutzer