Discount Calculator (Sale Price, Stacked Coupons & Tax)

Shoppers universally assume that stacking an "extra 20% off clearance coupon" on an item already marked down 20% yields 40% in total savings. In reality, retail discounts compound sequentially: on a $100 item, the initial 20% cut brings it to $80. The extra 20% is taken from $80, subtracting only $16, resulting in a $64 final price (36% total savings, not 40%).

In most US states (including California, Texas, and New York), manufacturer coupons do NOT reduce taxable subtotal. State tax law treats manufacturer coupons as cash tendered on behalf of the customer, meaning you are taxed on the full pre-coupon sticker price. Only store-issued instant markdowns legally reduce the taxable purchase price.

Retailers routinely inflate the "Original List Price" or MSRP days before major holiday sales events (Black Friday, Prime Day). An item that normally retails for $50 year-round is marked with a fake MSRP of $80 and discounted by 35% to $52. The consumer experiences the dopamine rush of a "massive discount" while actually paying $2 more than baseline.

When cart totals stand at $75, retailers advertise "Add $25 more to get $20 off!" Consumers eagerly add a $28 item they do not need. The total rises from $75 to $103, discounted by $20 to $83. The consumer spent $8 more cash to acquire unwanted inventory under the psychological illusion of "winning" a discount.

Electronics retailers advertise net prices "After $50 Mail-in Rebate." Actuarial retail studies demonstrate that between 40% and 60% of all mail-in rebates are never redeemed due to complex paperwork, strict 14-day postmark deadlines, and UPC barcode clipping friction. Unless a discount is instant at the register, never evaluate a deal assuming guaranteed rebate capture.