[Sig Sauer P220]

I must be doing something wrong. I always have to pay taxes on my internet purchases.

[Snoopers-868th]

That is because you buy from businesses that have a location in your state.

[KarlInOhio]

In addition to business having any office/store in you state causing them to have to collect tax from any purchase in the state, California (and maybe others) started playing hardball with computer purchases a decade or so ago. They told the major mail order computer vendors at the time (Dell, Gateway, a few others that have passed into history) "You don't have to collect taxes. But if you don't, you will not get any business from the state... don't even bother sending in bids." Most of the big ones fell in line and started collecting California sales tax.