Computer memory online

It is quite amazing the speed of which computers develop. I bought my apple Mac book 6 months ago with an up to date memory of 1 GB at that time, but just last month, I was shocked that there that computer memory being sold that were as high as 4 or 8 GB! I also want my computer to be as fast as possible as I was a solid gamer in the net, so I decided to upgrade my Mac memory to at least 4 GB and now comes the hard part, actually looking for the lowest possible price for this memory modules. I found one such site in www.memoryupgrad.pro where they have all kinds of modules including an Apple memory for my desktop at home. I am glad things like these are available online which makes it easier for me to locate.