Again, see if it is a redundant technology before you try and sell it, even if you do buy it.
I wouldn't think it was worth the hassle, of course, unless you buy it off your mate for ?20 and them sell it on for ?80. But then, think about this: who would want to buy it from you? You would have to have quite a lot of advertising before someone wants something specific as that, right?
Ebay maybe, but, i'm not even too sure about that.
Just do some reaseach init.