The deepest markdowns usually come with a condition, that the sale is final. The discount and the condition are directly connected.
A return is an expensive event
Handling a returned item involves inbound freight, inspection, cleaning or repackaging, restocking and often a second markdown before it sells again.
On a full-price item that cost is absorbed by margin. On a clearance item there is little margin left to absorb anything.
Final sale terms remove the possibility of incurring that cost twice on the same unit, which is what allows the price to go lower.
Certainty has an accounting value
Retailers hold a reserve against expected returns, which reduces recognized revenue on every sale that carries return rights.
Sales without return rights do not require the same reserve, so the cash and the revenue are both settled at the point of sale.
Clearing an aged category with certainty is worth a genuine discount, because the alternative is a balance that stays open for weeks.
The items chosen for final sale are not random
Final sale is applied where return rates are highest or where the goods cannot be resold, which is why it clusters in swimwear, intimates, cosmetics and heavily marked-down apparel.
Broken size runs also qualify, since a returned unit from a depleted assortment has almost no chance of finding another buyer.
Seeing final sale terms is therefore a signal about the item's remaining life in the store, not simply a policy detail.
Consumer protections still apply
Final sale governs returns of change of mind, and it does not remove a seller's obligations regarding faulty or misdescribed goods.
Those obligations vary by state and change over time, and a store policy cannot override them. Specifics are worth confirming locally rather than assumed.
The practical distinction is between an item that is not what was promised and an item that simply did not suit.
What the buyer should do differently
Because the exchange route is closed, inspection at the point of purchase carries the weight the return policy normally would.
Fit, completeness and function are the three things worth checking, since those are the reasons most returns happen.
Comparing the final sale price against a returnable price elsewhere is the honest comparison, because the two are not the same product on the same terms.
Payment method can restore part of the protection, since some cards carry purchase safeguards that operate independently of a store's policy. Those terms are set by the issuer and are worth reading before relying on them.