There are truly phenomenal lenses available in the 80-200mm/70-210mm range on the used market today for a pittance.
One of the reasons is the proliferation of the DSLR with the APS-C sensor. The 80-200/70-210 focal lengths become too long for portraiture and thus there is the temporary glut on the market. As DSLR full-sized sensor cameras begin to drop in price, which has already started to happen, those "forgotten" lenses will start to become more popular again. These slower-aperture lenses were fairly easy to manufacture (in the f/4-f/5.6 range) and the computer-designed formulas from the late 1980's and early 1990's are incredibly sharp.