There's a company called Flavourly, a bit of a hipster organisation that posts craft beers to its members. The beer is very good, but nothing special and a bit overpriced for my liking.
However every three months or so they need to clear out their old stock and sell it off cheap about a £1 a can. Then I buy it.
I much prefer my local beer shop, they just sell beer and a bit of cider.
I'll look out for your Purple Haze when I'm next there, the other sort will have to wait until I'm back in Amsterdam.