We understand your concern when your actual charge is different than what you were expecting based on your initial online receipt.
We do e-mail a link to the invoice to you as soon as we have the actual total. The initial receipt is only an estimate when it comes to your local sales taxes. That is why the online receipt says "estimated tax". There are so many variations in sales tax from town to town across the country that our system estimates the tax based on a State's average. We try to estimate accurately, but can obviously be a little off from what your local tax is compared to what we initially estimated.