Am I correct to believe it is the sellers responsibility to collect and pay the tax?
If I live in a Sales Tax Free state, and I sell an item through eBay (for instance…), and the purchaser is from a state that has a sales tax, eBay will automatically include the tax in the sale and shipping fee (if any…) and eBay will send the sales tax money to the purchaser's state treasury…
BTW, eBay even levies that sales tax against the shipping, since it is a service it is tax exempt, but they still charge it, I wonder if they actually send it to the state or if they keep their ill-gotten gains…
If I live in a Sales Tax Free state, and I sell an item privately (for instance Craigslist, Newspaper, Magazine, or Internet Advertisement, etc) and the purchaser is from a state that has a sales tax, I will not collect the sales tax. If the purchaser's state requires that sales tax be paid even from out of state purchases, it then incumbent upon the purchaser to pay the required sales tax.
Here is Virginia, if I were to purchase sales taxable items from an entity that does not collect the sales tax, I am required to pay that sales tax at the time I file my state tax returns… Yes, when yu fill out your Virginia state tax form, you are asked if you bought any items that were not taxed. And when you check that box, "NO", you are swearing an oath that you do not own any sales taxes for those purchases.
Items sold at Garage or Yard Sales are classified as "Casual Sales" and therefore not taxable in Virginia… Of course, if you buy a car at a garage sale, the DMV will collect the tax when you register it… And they charge you the higher of the two, the amount written on the receipt or the value of the vehicle in their "little blue book…"
If your Grandma gave you her car as a gift, it is not taxable, but there are a lot of "Hoops" you have to jump through to prove it was a gift…