Apple Store extra memery SUPER EXPENSIVE?

I am looking at the Apple store, wanting to buy a Macbook Pro with 4gb of memory. How on earth is the upgrade from 2gb to 4gb RAM cost 400 dollars??? Two matched sticks of 2Gb RAM modules DDR2 667MHZ cost around 100 dollars NEW. Should I just buy non-Apple branded sticks and put them in myself? Which brand does Apple use inside their MacBooks? Thanks for any help…!