The exact selected base
One 7.89 project set,one 5.79 watercolor kit and one 12.49 fingerpaint set total 26.17 USD. The tool stores 2617 cents. A confirmed 26.17 merchandise credit is valid and leaves zero merchandise. A 26.18 credit is one cent too high and is rejected rather than silently reduced.
Charges remain attached
If your actual shipping is 4.99,tax 1.25 and other charges 0,full merchandise credit still leaves 6.24 in entered charges. These are arithmetic examples based on your inputs,not live fees or a tax determination. A promotion's charge treatment must be checked in the actual order.
Unknown is not free
Blank shipping,tax or other charges withhold a full total. Enter 0 only when confirmed. Negative,exponent,over-precision and over-limit values remain unresolved. A known merchandise subtotal can be shown without inventing the rest of checkout.
Decimal edges are tested
An edited 0.10 price times 3 is 0.30. Exact 0.30 credit is valid and 0.31 is not. Likewise 47.99 times 2 is 95.98. Integer cents prevent floating-point residue from rejecting an exact full credit. Edited values are your quotes,not new observed public prices.
Keep tier eligibility separate
The calculator does not automatically apply the 541204 six-plus tier or a shipping membership benefit. Enter a confirmed actual offer price and avoid counting the same discount twice as both a lower unit price and another credit. No payment,address or order is transmitted. Merchant approval and checkout verification remain pending.
A zero-price boundary
If all selected quantities are zero,the merchandise base is zero. A zero credit is valid;even a one-cent merchandise credit exceeds that base and is rejected. Actual charges still need explicit values before a total is presented. This boundary helps prevent a refund-style input from creating a negative shopping total. The calculator does not decide whether a merchant owes a credit or whether a promotion applies to an empty basket.
Sources & scope
Checked November 5, 2026. Manufacturer and retailer references support the specific statements. Dated displayed prices are not final checkout quotes, performance rankings or performance testing. This shopping reference does not replace the exact product label or qualified individual advice. Current received labels and independent child-art/chemical-label/content/commerce review remain pending.