If the 850 is a manual transmission, non-turbo model, with a good service history, it should be a decent car, considering it's a '96 (later model of 850).

Automatic transmissions in 850s aren't renowned for ultimate durability.

You might also consider a 1995 940 Turbo, which is the pinnacle of development of RWD four-cylinder Volvos. A very solid car, with performance equivalent to an 850 5-speed.

-Sam