Core rule: section 12(3) excludes a genuine discount or similar trade allowance given on supply from taxable value. Free samples and gifts require separate analysis of supply, valuation and input-credit provisions; a zero selling price is not a universal VAT exemption.
Example: ordinary taxable goods are priced at NPR 100,000, with a genuine NPR 10,000 invoice discount. The net taxable amount is NPR 90,000 and VAT at 13% is NPR 11,700, assuming no special valuation rule applies.
Do not automatically use that calculation for goods given away free. Record what was distributed, to whom, why and at what cost or value. Rule 24 requires additional records for business samples and goods received or distributed without charge.
For a later price reduction, consider a properly supported credit note rather than retrospectively deleting the sale.