I would prefer that the 50% discount was reduced at retail because its immediately beneficial to the individual, but it could be administered the other way around.
Every penny of the discount would be created and rebated back to the enterprise giving it, by the monetary authority. That authority could be the FED in the USA, or some other national authority mandated to do so.
Example: Individual goes to the grocery store who has agreed to opt into the 50% discount/rebate policy and its rules. He/she buys $100 worth of goods and pays $50. The enterprise debits $50 to retail sales account and the monetary authority credits the account with $50. The individual’s purchasing power is doubled and the free and clear revenue available for the enterprise’s goods and/or services is also (potentially) doubled. All costs including profit and taxes are paid in full.
Example of 50% discount/rebate policy applied at both retail sale and at the point of note signing for a green electric automobile: The individual goes to the dealer and the $50k out the door costs including taxes on the EV is reduced to $25k at retail sale. Then, assuming creditability, the note (IMO best owed to the truly national publicly administered non-profit banking system) is reduced by 50% to $12.5k at 0% interest. (With the non-profit banking system the amount is simply written off and no interest is needed. With a for profit bank the monetary authority would simply credit the bank for the $12.5k and the individual would have to pay interest on the note.
Finance is necessary and doable for costly high tech economies to survive, but for-profit finance violates the “sanctity” so to speak of retail sale being the ending point for costs and the point where production becomes consumption (consumption is where any good or service LEAVES the economy and no one and no commercial entity has the right to charge one further costs other than the total financed, monthly for an agreed upon period without interest until paid off).
The 50% discounts ARE blunt instruments. Beneficial blunt instruments, and everything is accounted for. In the case of the second 50% discount at note signing, with the non-profit system the money is completely accounted for, but 50% of the total is simply destroyed with the debit-credit convention of double entry bookkeeping. No fuss, no harm.