She built a real business by herself using free web tools to build a site that may not look as pretty, but actually generates a lot of sales.

If you really have to develop a new site from scratch you should talk to a really good programmer to get an idea of the scope and approximate cost. You might also be able to find a couple dev shops to give you a free cost estimate. It would be in the $10-$100K range.

Again though if you are trying to start a clothing company or something, don't build a fancy custom website.