A few months back, there were bargains galore as many retailers cleared out their stock of 40mhz kit. I think most of that has gone now, though.
40 mhz is getting a little trickier to find in model shops, as unless you're a submariner, there is really little incentive to buy anything other than 2.4ghz sets, so demand is low. However there are secondhand sets to be had as skimmer owners offload their 40mhz sets when crossing over to 2.4ghz.
Ebay throws up a few bargains now and again. The model boat mayhem forum is another good source, sets come up for sale fairly regularlyhttp://www.modelboatmayhem.co.uk/forum
I saw a chap on Facebook looking to flog a new in box 40mhz Skysport 6. No mention of price, but I might be able to put you in touch if you're interested?