If you are a programmer, you can make your own site quite easily. Another option is to spend a good chunk of money for a professional to create one for you.
However, that's an expensive option. For aspiring micro-preneurs, I recommend a simpler and cheaper route-- go with a pre-packaged template service-- these include Godaddy.com, Yahoo Stores, Ebay Stores, etc.
No, your site won't look "professional" necessarily. However, in the beginning your main goal is to experiment. Most likely, you won't know what the hell you are doing. I certainly didn't... and honestly, I'm still mostly clueless. To start your own e-business cheaply, you've got to have the luxury of having plenty of time for trial and error. That means you probably can't afford to spend chunks of money for web hosting and web design. Save that for when you've figured it all out and already have a successful site.
Another key point to consider, when starting out, is how you can become more extreme. As a low-budget bootstrapping cyber-hobo, there's no way in hell you can compete directly with any normal company that has a bigger budget. As a tiny cyber-hobo, you've got to be unique.
How can you do this? Seth Godin recommends "going for the edges". By this he means, identify your unique qualities or strengths.... then push them to the farthest extreme. For example, I cannot compete with the giant English chain schools & their websites directly. Nor can I compete with huge corporate textbook publishers.
But one of my unique qualities and strengths is that I use only natural approaches that do not teach the analysis of grammar. Lucky for me, all the mega-schools and corporate publishers focus on precisely that-- grammar analysis. So one of my edges is "real English without grammar study". I NEVER use textbook-like activities on my site, I NEVER use contrived conversations on my site.... I use only authentic English--- meaning real conversations (unscripted), real movies (made for native speakers), real letters (not contrived by a textbook publisher), real articles (made for native speakers), etc... I'm always searching for more ways to push this edge... to provide more authentic, real-life, uncontrived English-- and natural ways to make it understandable for my website members.
Finally, one more point. The "edges" you choose must be in accord with your passions. The one thing you can't afford to be as a tiny cyber-hobo is boring. You've got to invest your heart and soul. As an English teacher, I'm passionate about this style of teaching. I deplore the traditional ways of teaching the language-- especially grammar-analysis. I detest the structure of the English as a Foreign Language industry. I detest the textbooks and the publishers.
I'm not just "interested in" this topic-- I'm a passionate crusader for it. In fact, I was fired from my last job in Thailand because of my defiance of traditional teaching methods and my refusal to use them.
You've got to find that same passion & crusading mentality and tie it to your little enterprise. If you want to sell your own jewelry, don't try to sell boring stuff that is just like what everyone else is selling. Sell YOUR art--- and make it completely and truly YOURS. Never, never, never think like a business person and ponder, "What do people want to buy... what could I do or make that would reach a big market".
Instead, think, "What am I crazy about, What do I love doing, and What can I do in a great and unique way". Find it, do it... then launch your website and seek out the other crazy people in the world who are on the same wavelength as you are. Leave the bland mass market to Wal-Mart and their evil brethren. Create something with heart.
Don't worry, if you are patient and persistent... you'll find plenty. For my part, I knew that the vast majority of English students want grammar-- and think its absolutely necessary. They are wrong, but I'll never convince most of them. Luckily, I don't need to. Because with the internet, I can slowly connect with the tiny percentage (but still huge number) of people who are looking for a teacher like me.
Trust yourself. Trust your passions and your genius. Accept your fears.
Then launch that site. That's when the real planning, adjustment, and experimenting begin.