Maybe it depends on the state? I’m in Georgia and just checked a few of my Apple invoices. A 99c app costs me exactly 99c, no tax is added.
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You are 100% correct about software sales. Georgia law says since there is no property being exchanged it’s not subject to sales tax. I didn’t know this until today. The law is kinda weird.
https://dor.georgia.gov/document/letter-ruling/lr-sut-2014-0...