how do you promote your business?

Depending on what your business is, you may find eBay to be a great place to promote it. You might put something up for sale on eBay, and the true value for you is not "whether or not the item sells" (which it may or may not) - the true value may be the interest that your listing generates in getting people to look at your eBay profile page - where they can find a link to your website and see what else you have to offer. :)