Help with Upgrading RAM?

Hey I was thinking about upgrading my RAM in my MacBook. I don't know much but it's a white MacBook with a 2.4 GHz Intel Core 2 Duo Processor and for Memory it says 2 GB 667 MHz DDR2 SDRAM. it's Model ID is 4,1 so i think it's 2008? not sure I got it from my brother The Memory apple is showing me is $100 but Amazon is showing the same thing (i'm pretty sure) for $18. Is it the same thing? Can I get it off Amazon and it will work the same? Also is it easy to install it? Also how much RAM can I put in this computer? I've never done something like this before but would love to do it myself. Thanks for any input.

~Tim

I'm an amazon guy. Is this the same thing? 4gb ram And about installation? Do I need any special tools? Is it easy enough to figure out? Thanks so much for the help

which is better was going to order today

http://www.amazon.com/Upgrade-MacBo...1-2&keywords=200-pin+DDR2+SO-DIMM+RAM+macbook

http://www.amazon.com/Memory-Module...1-4&keywords=200-pin+DDR2+SO-DIMM+RAM+macbook

http://www.amazon.com/Crucial-PC2-5...&keywords=DDR2-667+(PC2-5300)+200+pin+SODIMMs

is there a difference?

I'm confused because I want to make sure I don't order a memory module that won't compatible to my macBook

Thanks for all the help guys. I got my ram in the mail yesterday installed today and its working great. Programs open noticeably faster and it was easy as hell to install so thanks a bunch!

~Tim