$20 and a pizza. Seriously, they are nice but old. Your friend assumes all of the risk buying something this old (even though they are of good quality). I wouldn't ask for more if this is a friend that you value.
yup, nice speakers, but also quite dated as well. if you were outright selling them you might be able to get $100 out of them considering the cost of new klipsh floorstanders are very high, however given the age of the speakers and possibility of having issues arise i'd do as colgeek suggested to avoid any hard feeling should something fail down the road.