You and half of the rest of the world could all download a copy of the same template and so your site becomes a clone of many others.
You also have no real claim to how good your site could end up by looking since all you've done is used someone else's work and filled it in with your own text and many of the templates insist on you keeping a link to the original designer on your pages which robs the site of any professionalism. If you remove the link without paying for the template you can end up in serious hot water, although I'm not suggesting that you'd do this. Some people try it though.
You will also find that many of the templates are quite recognisable and a lot of people will see them for what they are straight away.
I am assuming that you want a template for a business site rather than the nature of your business being to sell templates online.
These were among the top links in a Google search for website templates.
I can't recommend any of them, never having used them, but good luck with it anyway.