I just received an email today from Buyapowa for Crest 3D White Professional WhiteStrips. From online reviews, these seem to be too good to miss so I decided I would join this co-buy; my first one!
There are just under 4 days left to get some, link here
They also have other co-buys such as Elizabeth Arden Eight Hour Survival Kit, I am quite tempted by this but I have so much make-up already I might just have to give it a miss. (Link below too)