I do Web Coding: PHP, Javascript, HTML,...
Almost anybody can build a website these days; there are templates available that allow you to build a site without needing to do any coding. The problem is that if you build your site that way you are going to end up with a site that looks like everybody else's site. You are also going to have a site that is limited in the features that it can offer. This is why if you want to have a professional looking site you need to hire a web coder.
Over the last few years web coding has gotten a great deal more complicated than it used to be. The days when all you needed to create a website was a basic understanding of HTML are long gone. Of course you can still create a website this way but it will look very dated and amateurish. These days building a website requires that you know a wide variety of coding languages so that you can add the features that people expect to find when they visit your website. Without them you are going to leave a bad impression on your visitor.
Of course there are more reasons than just impressing your visitors that you are going to want to make sure that you can find somebody who can code your website properly. The biggest is that it allows you to make your site a lot more interactive. This is important from a marketing perspective since it means you will be able to tailor the content of your site to your visitor. That means that based on what they have looked at on your site you will be able to recommend relevant products to them. This will greatly increase the sales that you make from your site.
In addition to making your site more interactive proper coding also makes sure that your site works properly. This is not a small detail because people are not going to hang around your site if it doesn't work properly. One of the things that makes the internet so different from other retail environments is that it is so easy for people to leave and go someplace else. If you have a site that doesn't work the way it is supposed to it is basically two clicks of a button for people to go to another site to buy. You can't afford to have a site that isn't coded properly.
One of the issues that you are going to face when you are trying to find somebody to code your site is that there are now so many different coding languages it is hard to find somebody who can do them all. This is why you need to find somebody who is comfortable working with all of the major ones that are likely to be necessary. It will save you a lot of hassle if you don't have to find different people to do different parts of your site.