Paying sales tax for marketing materials

Can anyone explain to me why we pay sales tax for our marketing materials? I was told I need a sales tax number on file, but when I contacted the CO dept of revenue, I was told that since this is a service business and I don’t produce anything, I don’t need a sales tax license.

You need a tax number if you resell materials. You are the end purchaser since marketing stuff isn’t being resold, it is being given away.