Well. I guess I should just shush and thank my lucky stars re Amazon & sales tax then. I could've just looked it up earlier but figured asking was easier... but your answer didn't help me any, lol. According to what I saw on Amazon the state I live in is supposed to pay sales tax (there are 25 listed, I think it was 25) and it shows as "Estimated sales tax". I have never, ever paid any sales tax on anything ordered from there - and I just ordered stuff from there this month. A quick Google (with no links actually clicked on) showed that there were 20 states as of the beginning of 2014 that were/are supposed to pay sales tax.

editing to add: The exception to sales tax is gift cards. It also says that stuff paid for with a gift card may be charged sales tax, or something like that. Which makes me think that you may or may not have to pay sales tax if you're paying with a gift card. The stuff I ordered this month was paid for with a gift card so it's possible that may be why I wasn't charged sales tax. (But that's not the only time I've ordered from Amazon this year - the other times I used my debit card.)