£65.91 @ Amazon
£62.85 @ Shopto.net (out of stock)
Whilst it's still a bloody expensive peripheral - those in the market for it can save a few quid with Zavvi's £6 quidco discount code, plus the 3.5% quidco cashback & apparently the walkers 10% code works on top of this - meaning you could be looking at getting this down to around £50 if all the cashback comes through.
Obviously I appreciate that not many people will be buying this outright, since you can only use it with the new game - but since the combo pack of the instrument and game is about £100 most places - with the supermarkets likely to do deals on RB3 on release, i'd imagine it'll be cheaper to buy them seperately!
I also accept that these plastic instruments come right down in price once HMV et al have piles of them sitting around. This is the best price going for it right now, not a few months time!