I am thinking about buying a MacBook Pro laptop off of ebay, and I see that it is very expensive to buy lots of ram included. I've heard that its much cheaper to install your ram by yourself. I looked at 2 GB of ram for a MacBook Pro and it was only 150 $$ on eBay. Is it easy to install the ram or hard, and how do you do it. Also how many slots are there? Are there 4 like on most pc's or only 3. As I have seen is the max on Apple.com