-newegg is a website with good pricing, wide selection, and while it's main focus is computers, it also sells cameras, and other electronics. click here to take a look.
-Amazon is a popular place to buy anything online, and it sells many computer parts, full computers, laptops, and almost anything you could want to buy. click here to visit.
-fry's is more focused on computers than newegg and amazon, but also sells other things such as refrigerators, and televisions. On newegg you can order onlina and get things shipped, like on newegg or amazon, but if you don't like online shopping there are also many real store locations you can visit, although they may not be very close.