Are you referring to when you renew your plates every year? Many states tax on value every year. Goes down as the vehicle gets older. If New Hampshire is a no tax state and only charges approx $10 for plates every year I would change my residence to that state. First, I would check their other taxes. Different states have different methods of getting their tax dollars.
I would not just register my vehicle at a relative's home in another state. I think you are asking for further problems. We had some relatives that registered their CA vehicle at a friends home in MT. They finally got caught and it was very expensive. You may have to pay all the back taxes and interest.
2012 Jay Flight 19RD TT
W/thermal package: R19 walls, R22 roof, R24 floor
2008 F-250 Ford FX4 6.8L V10/4.10 rear axle
Curt class V hitch
Reese trunion WD with dual cam
AC6CV/7 ex-W8RUR since 1954