2240s are without doubt the best value air pistol around, until you start modding them!
Not sure on sales for modded pistols, if I were to sell any of mine I would strip the mods off and sell separately.
My scoped 2240 cost about £220 to put together, my 2250 is close to the £500 mark (not much of the original gun left!).
Buy new for £75-£80 and then save up for additions when you can. Lightening and cleaning up the trigger and hammer are a good (free) place to start while you save though.
Great Deals with : Dave Dee, Dozy, Beaky, Mick & Tich