Buying Memory, Your wisdom please

Hi i wanna upgrade the memory in my friends laptop.

I know it takes DDR2 PC2-5300.

But what is the difference between
http://www.ebuyer.com/product/119282 at 17.99 (crucial)

this

http://www.ebuyer.com/product/123910 at 16.00 (ebuyer)

this

http://www.ebuyer.com/product/95741 Kingston at 17.00

Should i buy the cheap one? i mean is there actually any difference? or should i buy a complete different type?

cheers

Alex