Ya, just buy it in California and get a HOV sticker
Works great as long as you can register is in another state. Tesla is moving to all online sales though and closing dealerships so may not be possible much longer.
Your tax rate is based entirely on your registered vehicle address, so it doesn't matter if you fly to Missouri and drive the car back. You'll still get the California tax rate.
If you have an address in Oregon you can buy it there and register it there, $0 sales tax.
It doesn’t work unless you have another state address that you can register the car with. Otherwise you get taxed based on your address, and any applicable state eligible rebates.
You get taxed based on the address you put though for where the car will stay, this wouldn’t work unless you have an address that you can use in another state? (Not sure either)