Hi, its not just a matter of cheapest.. It's a matter of who has stock.. very hard to get the 4g model but the 2g is easier and more inferior in my opinion.
I have both, got 2g surf from pcworld before xmas for £199, it was too small the hd and ram for what i wanted, so managed to get a 4g from play last month, had to wait till they got restocked though.. £220.
http://eeestock.cpjackson.co.uk/here is a uk online stock checker.
If you are just gonna browse the internet and dont mind using xandros linux with limited functionality then the 2g will do you. If you want to be able to upgrade the memory and /or put another linux or windows on it then 4g minimum.
