You can get a temporary vehicle permit if you buy a vehicle while serving as a nonresident military personnel.
The permit allows you to use the vehicle in Washington while you apply for out-of-state registration. The permit:
Nonresident military members who apply for this permit are not subject to sales tax, use tax, or motor vehicle excise tax during or after the 45-day period of the permit unless one of the following applies:
Call us: 360.902.3900 (TTY: Call 711)