I've bought stuff online since 1989. Back then, it was mostly software. More recently it's been almost entirely thru Amazon and other allied dealers for all kinds of merchandise.
I haven't paid a nickel in sales tax on thousands of dollars in purchases over the years until just now, when I placed an Amazon order for a $20 windscreen for a Heil PR40 microphone, purchased thru Musician's Friend.
It was only $1.49. But that's an ugly start. And, of course, I blame Bush.