This is what I found on Military Sales webpage:
"In the case of State Sales Tax it is impossible to list definitive criteria, as each individual state views both rates and liability differently. As a general rule you should expect to pay some form of tax upon first registration in the USA. However, as a military person you may qualify for exemption or if the vehicle has already been bought and owned out of state (sometimes for a specified time period) this may also fulfil any criteria for exemption. It’s always wise to try to obtain first hand information from the appropriate local office. For an overview of the various State rates click
www.taxadmin.org then navigate to the relevant section."
And about import tax:
"Import Tax is charged at 2.5% of the total value stated on the Bill of Sale. As a general rule the criteria for free (non-taxable) importation is that the owner must have been stationed abroad for 140 consecutive days and has taken physical possession of the vehicle while stationed abroad. A copy of official military (PCS) orders must accompany the vehicle being shipped and as some US ports of entry stipulate a minimum mileage requirement in order to avoid Import Tax, it is also recommended that your vehicle be shipped with a minimum of 500 miles at the time of importation. Depending upon whether you are Military, Civilian (GS) or DOD contractor, the rules can vary. If you’re unsure just check with the relevant department or visit the official US Customs Website and navigate to the relevant section. www.customs.gov/xp/cgov/import/infrequent_importer_info/personal_vehicle.xml"