There are a number of ways through which you can buy your computer online.
For one, you can just visit one of the online stores dealing exclusively in computers. Some are manufacturer-affiliated (or even manufacturer-run) online computer stores. Others are run by ‘webpreneurs’ who simply purchase computers cheaply and sell them at a profit. Some deal in new computers, whereas others deal in used machines. What you can be sure about these stores that deal exclusively in computers is that they only offer their products at ‘typical prices;’ for they are in sync with the market trends.
Secondly, you can try your luck at one of the online classifieds sites; where an individual or business with a computer for sale put up advertisements requesting for interest. The beauty of going this route in your search for a computer is that you can find a truly good computer for sale going at an amazing price: for some of the sellers here are really just looking to get rid of machines to de-clutter or in readiness for an impending move. And in the best of online classified websites nowadays, if you can’t find the machine you want, you can always put up a private ad, asking if someone might have such a machine for sale.