In the past and for many years, I owned an Apple computer store which also sold a variety of manufactures' computers (most of those early computer stores are long since out of business). Since selling off my computer store business, I continue to teach a lot of classes about genealogy programs and online resources which gives people the idea I might know something about computers and so from time to time people ask me for recommendations on the purchase of a (new) computer for doing their genealogy. Often, when I give a reccommendation, the person comments that this is not what their son (fill in the blank) or whoever told them and they start to argue with me. Subsequently, my recommendations have become more and more general over the years.
Before asking, you may want to know a little bit about the person you ask as well as a little bit about computers. I find that when any of my friends ask their younger relatives for assistance in purchasing a computer they soon find out that the younger relative is more interested in what he or she can do with the computer than what my friend might want to do. But, as a genealogist you may not need the fastest game-playing graphics computer for your research, a cheaper off-the-shelf model might do just as well.
There have been vast changes in the way computers are sold today compared to the past. The first personal computers required a lot of hand-holding and the customers expected the salesperson to be knowledgeable.
About all that you really need know today, is that most computers are sold either over the Internet or through a big-box store such as Costco, Walmart, Sam's Club, Best Buy and a host of other businesses. Computers are sold like a commodity. It is possible that the sales clerk in the store where you buy a computer, may not even know how to turn it on. This does not mean that you won't find a computer expert in a mass merchandising store, it is just unlikely to happen.
Today, the price of a new computer is dependent on 1) the speed and capacity of the processor, 2) the amount of RAM memory, 3) the capacity of the hard drive, 4) the number and type of connectors such as USB ports and others, 5) other equipment included in the sale, such as a mouse, keyboard, or monitor. Usually, newer computers come pre-loaded with a lot of software. The faster, newer, larger capacity computers cost more than slower, older, smaller capacity computers. But electronics in general change so rapidly, today's slower, older computer might be only six months old.
Because the price of the computer is usually a function of the newness of the equipment, all you really have to do to start an investigation is find out the latest release of processors from Intel or AMD. If you buy from a major outlet you are unlikely to find anyone in the store who can tell you anything about the product you are buying except where the box is located and its price if the printed price card is located nearby. Buying online, you are also left entirely to your own devices in finding out what it is you need or want to buy. This is the main reason I get the questions about which computer to buy. But if you realize that the major retailers turn over their inventory very quickly, you can usually find the latest and fastest release of processor in one of the more expensive computers for sale off the shelf. Unless you are heavily into video, manipulating photographs in Photoshop or some other memory intensive activity, nearly all of the computers available today are much faster than you will ever need for genealogy. In fact, the least expensive computers today have more computing power than anything that was available even a few years ago at any price. My iPhone has more computing power than most of the desktop computers I have owned over the past 28 years.
So what would I do if I were buying a computer? First, I would go to the library (or look online) and find a very recently published book on the basics of computing. I would make sure I knew the difference between the computer's RAM memory and its hard drive memory and other basic information. Then I would spend some time looking on line and comparing prices. If I didn't understand the differences between the computers at different prices, I would either research the words until I knew what the difference was or ask someone who really knew the answer. I would probably read some of the reviews of the products online.
For example, you can spend $13,000 on a new car or $130,000 on a new car. Do you know why the first car costs $13,000? Or why the second car costs $130,000? If not, I suggest you shouldn't be buying a car. You also might want to know the difference between a Sony Supermicro Extreme Computer Editing Workstation for $6,999 and an HP Workstation Xw5000 for $70 new. Maybe not, but you might want to know why you would probably not want either one to do your genealogy.
It is still true today, that with computers, you can buy a complete system, ready to operate, or you can buy each individual piece and put the whole thing together yourself. Some people think the only way to purchase a computer is in pieces. I do not find many genealogists who think this way. Usually, genealogists would rather get to work rather than spending time trying to get a pile of computer components to work together. A variation on this theme is the relative who offers to "build" you a system from scratch. Before you accept this offer, you might want to see what you can buy ready-built off-the-shelf before taking him up on the deal.
Once you have a feel for the price and performance of a particular computer system, you will probably come to a conclusion about which system you want to buy.