i got mine from my gym, but i have seen in a health shop somewhere around, not holland and barratt though.
this is mine
i think i paid £3.50 for mine, it seems like an extra expense but it really does work - i used to take the protein over the bath just in case i couldnt hack it.
also, i switch to a different (cheaper!) whey protein around a month ago - i found this blends better without the shaker and tastes better too so i use it for fruit smoothies.
what are you using? are you in the uk?