You will find that not many people will be able to accompany the older machines PC parts because they are so specific, but I know of one place that will have everything you need. They deal specifically with MAC's and it shows in their name. My other two selections are extremely good with computer hardware as a whole and will do well with the newer cheap apple computer parts that you may buy. I will list these options below.
1. MacMall
2. Newegg
3. Amazon
MacMall
This company is the one I spoke of that deals only with Macintosh products. They now have to spread their computer hardware to almost everything because that is what is available now. So they are not a niche anymore so they will have to advertise how they do a lot more things now, which can be a good thing for them. They have good deals and can save you some cash if you look them up every so often especially during the holidays.
Newegg
Newegg is a favorite of mine because they are the new computer hardware kings! They have every type of computer parts you can think of. They have years of experience and people voice their opinions good and bad within it so you can see what might or might not happen. I also love that they sell refurbished computer parts as well. These are computer parts that were maybe opened or barely used and have been re-certified by the manufacturer. They have moved on to other appliances as well, but ignore that. They are just trying to be the online electronics Walmart!
Amazon
Everybody knows who Amazon is and I really don't have to describe them. They have just about everything and they are the online Walmart. They bought egghead computer hardware a decade ago and now use that to do their computer parts section. Egghead used to be the king for computer hardware so they quickly bought them up to gain their market share. They have great prices as well and great service. Returning things can take a while sometimes because of they way they work with their service providers. You won't find this problem with Newegg.















