There are several things to consider when buying carpet. This article can't describe all the considerations in detail. But we can at least list what those considerations are. This will help you understand what you need to familiarize yourself with in order to buy carpet.
When buying carpet, the first thing you think of may be the color. This can be a trap. If you decide you absolutely have to have a certain color, you may find yourself stuck with a carpet material that really isn't right for the room you're going to put it in. Familiarize yourself with the different sorts of carpet fiber that exist and decide which one is right for you. Almost all US carpet sales involve synthetic fibers-- nylon, acrylic, polyester, or polypropylene (olefin). Each has strengths and weakness in terms of standing up to different sorts of stains, dirt, and heavy traffic. Think about how the room will be used and how long you want the carpet to be useful for before it needs to be replaced. If you absolutely must have a natural fiber such as wool or cotton, you'll definitely have to look around to find a seller and you'll be limited in style and color.
The two basic styles are cut pile and loop pile. All carpets start out as loop pile carpets, with loops of yarn rising up from the base. Cut pile carpets are constructed by cutting these loops. There are also hybrid "cut and loop" carpets that have some of the loops cut, others left intact. This can provide different textures and patterns. Cut pile is the most common, but loop pile has become increasingly popular. You can inspect both styles at a showroom and decide what's right for you.
Color is important, of course, but there are a few things to think about. Consider the lighting of the room where the carpet will go. A color may look green under the fluorescents of the showroom and brown under the dimmer lights of your family room. Also remember that lighter colors can look great at first; but they may also be more likely to show stains and dirt. Finally, of course, think about the rest of the decor in the room and how the carpet will match. If your decor is eclectic or likely to change, neutral colored carpet is best. The bolder a color statement you make with the carpet, the more trouble you will have matching the furniture, pictures, and other decorations to it.
There's an old saying that if you can only have good carpet or good padding, choose the good padding. That may be overstating things a bit. But the reality is that buyers think about padding less than they ought to. Make sure the padding will give you the comfort you desire and will hold up well to wear and tear. Many retailers buy padding in bulk and will try to sell whatever they have as "standard." If that doesn't meet your standards, ask them to order something else.
Retail carpet is the most expensive way to go, but you do get good service and advice. With a little work, you may be able to find a discount carpet wholesaler or an online carpet seller that has the style you want at a more reasonable price. Shop around.
Remember when reselling your house, the carpet may be the one item that makes the largest impression. Consider re-carpeting before selling. To do this, you don't need to select the most expensive or the most durable carpet. It's the look that's important. Find the best looking carpet for the lowest price that you can and you'll recover the investment when you sell.