Use it now. Within the next 6 months. Within the next 12 months. No plans to use it. Online malls are often a good way for inexperienced online retailers to test the market before they commit large financial resources to a standalone Ecommerce site.
Many businesses start in an online mall, then graduate to their own sites.
The easiest option is to hire a developer to deliver a turnkey Web site to you. Cost varies from several hundred to thousands of dollars, depending on the scope of the project. For the purposes of this article though, we're assuming that you're going to develop the site yourself. Understand up front that you will save money, but you'll spend a lot of time on the project - if you do it right. It's time well spent though.