No. We do not charge sales tax, but if you are a US citizen, it is your obligation to report purchases and pay sales tax in at least 21 states if you take delivery of your metal. You may also be responsible for taxes on any realized gains made in your positions, depending on the type of account you've chosen. You should consult your tax professional to understand your specific tax situation.
VAT is not applicable for metal going into storage or delivered to a US address. However, if you have your metals delivered to an overseas address, VAT may apply, depending on local laws and the storage location from which your order was sent. Be sure to consult local tax laws before taking delivery.