Although it may be tempting, don't go with the lowest price, as there's a good chance the quality will be low as well, or you'll actually end up "paying" more in the long run with your time and/or aggravation. Ikea's prices are cheap because you have to put the furniture together yourself. And furniture purchased from Big Lots or Walmart is cheap is because it's probably not going to hold up very well over the years. If you're a roofing contractor and you find it difficult to compete with other roofers who charge half the price, just wait a few years and those homeowners will be ready to get a new roof when their "bargain" roof fails. The saying, "You get what you pay for" applies to most products and services!
When you're comparing website designers, you should compare apples to apples, but that can be difficult. A small 3-page bargain basement web design should be cheaper than a premium 15-page website with all the bells and whistles, although in reality that's not always the case. Other factors, such as what the website designer does "behind the scenes", search engine optimization, off-site marketing, even the web designer's experience, can affect the price of the website. You can have two websites that look and act exactly the same, but one will show up on the top of Page 1 of Google Search, and the other won't move beyond Page 8; in that case, the website on Page 1 might be smaller and with fewer pages, but might cost more because more was done behind the scenes to get it to rank better.
Many variables can determine the price of a website. If your web designer is a small one-person firm, they may charge you less than a large company with several designers on their payroll because they don't have as much overhead. But what if the smaller web designer provides a higher quality product, a manually hand-coded website (which most web designers don't provide), and better personalized service, and the larger company just outsources their work to another country like China or India? In that case, the larger company may actually charge less because they're not really doing the work, and you may get a generic "cookie cutter" website. Also, if the web designer is also doing SEO (search engine optimization – which is necessary for every website, but something that not all web designers are skilled in), online marketing, social media, a logo, etc., they may (and should) charge more than a company that's simply throwing together a quick website without proper SEO or other online marketing services.
Since there are so many variables in determining the price of a website, how do you find a good web designer? Obviously if the company doesn't have a website of their own, or their website doesn't include links to other websites they've designed, you should think twice about hiring that company no matter how cheap they are. On the other hand, if the websites they've designed look great, how do you know they're actually good quality websites or not? The only way to know for sure is to check "under the hood", much the way you would when buying a car. A beautiful shiny car isn't much good if the engine is bad. But as a consumer, you won't know what to look for; only an experienced web designer who does manual website coding understands what's going on "under the hood" of a website and can determine if it's designed properly, has adequate search engine optimization, etc.
Check out these websites to see what the going rates are for web design, but these prices are ONLY for the website, and do NOT include Search Engine Optimization, Online Marketing, or Maintenance. Keep that in mind when your web designer gives you a quote!