I'll have to go look that up, because (don't take this personally lol, definitely no offense meant at all) I think you're wrong on that. If you purchase something from an online business that is located in your own state you pay state tax. If you purchase something from somewhere outside of your own state (and that business doesn't have any locations in your own state at all) then you pay no tax. I'm pretty sure that's how it works. But... What I'm not sure of is if you purchase something from 'inside' your own state and you have it sent "out" of state, that's where it's confusing for me. I'll see if I can find the tax info and to also find out if every state is the same too.
We here have the pleasure of dealing with county and city taxes also, so following what I said above, if anyone that lives within my county purchases they pay county and state tax, and if they are within my city they pay county, state and city taxes. Basically meaning that it's where the customer is purchasing from not where they are having it shipped to... but as I said I'll go look this up so I make sure, and when I find the info I'll post the basic thing here so we all know for sure lol. I don't want to confuse anyone else anymore than I already have... including me

Yes, you are correct. That is why is based on shipping destination not order origination. If you order something from Dell and you live in Texas and you have it shipped to Michigan, since Michigan has no Dell office there will be no tax applied to the order. Just because you live in Texas and Dell has an office in Texas does not mean you will be charged tax. I have actually gone through that process with Dell before when I ordered a computer for my parents who live in Michigan when I was in Texas. No tax was applied to my order.
Fun stuff......
