A better riff on Amazon - be an Amazon buying service in a state with no sales tax, make purchases for others then ship the purchase on. The sales tax on a $2000 laptop/camera/whatever isn’t trivial.
A good idea for expensive items. I do know ordering stuff for people who live in another state and having Amazon ship direct, does result in the sales tax charged for that state. Buying a cheap item, like a bar of soap, having it shipped to yourself then sending it to them would be pointless.
I live in Los Angeles County. With all the state and local sales taxes, it’s about 9.5%.