Didn't find out the price as well did she? If I ever go under a bus a lot of people are getting some bargains if my stuff gets sold for what Mrs M thinks it cost!
Tell her you're selling one/some, pick your least favourite and stick an advert on here for proof. Price it to get yourself a mention in the Macks thread, so it doesn't sell but if it does you're quids in. Chances are that'll buy you enough time for the whole thing to have been forgotten shortly after your new toy arrives.