Electronic, e-ink, price tags.
Centrally linked to a shop back office workstation. You can turn the entire shop upside down twice a week and the actual work to change the tags would be negligible.
And for what it matters, lets assume a very large nation wide chain, like Target. The stock leaves their supply wharehouses unmarked, as it should. The cargo is then delivered to the stores, the tags printed (waste of paper), with full price, and the shelves restocked. Each store has to deal with their local taxation or absence of it.
It is not a very complex endeavour.