Lovehoney are selling what they call a "Dressage Vibrawhip Vibrating Whip" - what I would pedantically call a riding crop - for £5, including postage. It has several vibrating speeds so you can adjust it to your liking. If like me you treat spanking and whipping as a prelude to sex, it's quite sensational - I'm still quivering from this morning's session!

Here: http://www.lovehoney.co.uk/product.cfm?p=7833



Needless to say, I have no connection with Lovehoney except as a very satisfied customer.