If the shop allows you to run up a tab, you can pay it off with legal tender. If the shop does not extend credit to you, you may not take the goods unless you have something the owner is willing to accept in trade. If the owner demands only gold or silver, you cannot legally pay with a bank note.
If you leave bank notes of sufficient value and run out, they are very unlikely to attempt to prosecute you, but they could, both for the theft and the nuisance of leaving your property lying around in their store. And the case would probably be resolved on appeal somewhere, with one judge arguing that the state has an inherent interest in having its primary currency universally accepted by all businesses in its jurisdiction, and another arguing that the state is overreaching when it tells shopkeepers what they must accept as payment.
If you leave bank notes of sufficient value and run out, they are very unlikely to attempt to prosecute you, but they could, both for the theft and the nuisance of leaving your property lying around in their store. And the case would probably be resolved on appeal somewhere, with one judge arguing that the state has an inherent interest in having its primary currency universally accepted by all businesses in its jurisdiction, and another arguing that the state is overreaching when it tells shopkeepers what they must accept as payment.