I want to say from the outset that I have not investigated this story independently. I do not claim that this practice will work in any state. But there was an article recently in a Framingham, MA newspaper about people using a Montana LLC to purchase RV's sans the sales tax. The practice is to set up an LLC in Montana, and that company will buy the vehicle. Montana will allow you to register your vehicle in their state. But, according to this article, Montana will not share any information about the owner of the LLC that would allow a given state to track them down.
The problem is this: this methodology relies on Montana's secrecy and on MA not being able to find you. The newspaper contacted Ann Dufresne, the director of communications for the Massachusetts Registry of Motor Vehicles for a comment on this. Ann warned drivers would face stiff penalties for trying to avoid the state's sales and excise taxes and other fees.
A person who drives a car in Massachusetts for more than 30 days is required to register and insure it here and pay the sales tax, she said. Residents who don't register their vehicles here could face more than $6,000 in fines and potentially have their license suspended, according to state law.