I have received an email from B and H saying that as of April first tney will be required by federal law to charge the correct sales tax according to the state in which you live, sigh no more free lunch
About time. There was never a free lunch. You should have been declaring and paying the state sales on internet purchases all along if your state has a sales (or use) tax. The bookkeeping has finally been updated to make the internet merchants charge it at the time of purchase.
My state requires that if you buy anything, other than food, in another state you are supposed to pay the sales tax when you buy it and then report it and pay sales tax again in my state.
For big ticket items like an automobile you may be able to get the sales (use) tax paid in the state of purchase if you can show you bought it to use in another state.
Say if you moved to California to take a new job with a car. You will have to pay use tax to California unless you purchased the car before you took the new job. If you have to pay the use tax to California you can apply and get the sales tax refunded from the state where you purchased the car.