Nighthawk, not splitting hairs, ok I am, but I believe you only collect sales tax. The state and municipalities set the rate and collect, you are simply the middle man.
What I can't figure out is why don't many gun dealers do the 'out the door' anymore? Just get your total and back the dollars and put that toasted the tax if you want to be on the up and up.
That is because some people do not pay sales tax. People in history have done this for years. Some have been caught some have not. Here is an example of one that was caught Al Capone. Speaking of Lawyers Dr. Tad Hussein Winslow, wasn't there lawyer call Gene Stype that got in trouble for taxes in Eastern Oklahoma not too long ago. I may be wrong but I think it was for not paying his taxes, and doing some under the table dealings..
But you are right always look at the grand total, and make sure you are getting what you are paying for. Apple for apples. Many times, a buyer will think he is getting a good deal only to find out that the seller has taken things out of the package, or it was last years model. Always check, and as if it has a lifetime warranty. Make sure that there are not going to be any add on charges after the sale. Also you do not want to order something from a site for a great price only to find out that they really do not have that item in stock, and it was just a way for them to get you to their site. These are experiances that I have had customers tell me about. You want a dealer that will be there tomorrow.