I had a look on Amazon, and its a bit weird. Ive always stuck to well-known name brands, like Kingston, and I see 4Gb micro sdcards by them going for £10-£15! That's compared to eg a 32Gb Kingston for £5!
Meanwhile, though, there are actually quite a lot of non-name brands Ive never heard of before selling 4Gb micro sdcards for £4-5 each. Like who the f**k are Cloudisk?