No. There is nothing inherent about sales tax that makes written prices shown pre tax. In Japan pre VAT prices are regularly advertised to consumers. In Denmar

No. There is nothing inherent about sales tax that makes written prices shown pre tax. In Japan pre VAT prices are regularly advertised to consumers. In Denmark receipts shows percent and nominal VAT of every purchase. There is nothing defining to sales tax that makes it impossible to have sales tax and requires retailers to advertise post tax prices.