Can you use a coupon code on sale items?

Usually not. Most discount codes exclude sale, clearance and already-reduced lines, and almost no checkout explains that when it rejects one — the code simply fails. The exception is worth knowing: codes written as “extra 10% off sale” are built for reduced stock, and a minority of shops let a sitewide percentage stack on top of a markdown.

How to tell in thirty seconds

Add one full-price item to the basket and try the code again. If it takes, the exclusion was the reason. If it still fails, the problem is something else — most often a minimum spend, which is covered in why a code gets rejected.

The choice nobody frames properly

When a code will not apply to reduced stock, you are not choosing between a discount and no discount. You are choosing between two discounts:

• The sale price on the item you want, with no code.
• The code on the full-price version, or on a different item that qualifies.

A 40% markdown beats a 15% code almost every time. A 10% clearance line against a “$30 off $150” code is closer than it looks, and on a larger basket the code often wins. Work it in money rather than percentages — percentages of different numbers are not comparable, which is exactly what makes them persuasive.

Where the stacking rules do hold

Three cases come up often enough to check for:

• Free delivery codes. These apply to postage rather than goods, so a markdown on the goods rarely blocks them.
• Category codes during a sitewide sale. If the sale is automatic rather than a marked-down price, the item is technically still full price and a code may apply.
• Newsletter and welcome codes. Often written with fewer exclusions than public codes, because their job is a first order.

When the price is already cut

If a code will not apply, the reduction may already be on the price. Products lists items with what they cost before, and deals are the ones where no code is needed at all — the money is off before you reach the basket.

One warning on struck-through prices generally: a line through a number only means something if the number moved. It is worth a glance at whether the “was” price is plausible for that item rather than taking it as given.

Before you buy either way

Check what is ending soon at the same shop. A better code with three days left is common, and it is the sort of thing you only find by looking.