Tis is, again, not for this thread. All of this is still in production in one form or another, so you can just go to GWs onlien store and tally it up, and then cut it by 30-70% depending on condition. This you can do yourself; we're not going to do it for you:)
As for selling it - tough choice, but if you have the time you are likely to get more money by selling it piece by piece (well, unit by unit) but you risk getting stuck with a unit you have to throw in the end. Othersie you can break it down in lots; farseer and guardian with platform in one, aspectwarriors with falcon in another, bikes and vyper in a third, and so on, and in that way get rid of less intereting units by tacking them on to the more interesting ones. Good luck.