If goods in a shop are on (special) offer, they are being sold at a lower price than usual.

Strawberries were on special offer today so I bought loads of them.

Try not to buy stuff you don't need just because it's on offer.

I usually wait till they're on special offer and then stock up.

I notice champagne is on offer this week.

It has some really good wines on offer at the moment.

See also: offer noun