The 'price' group
These nouns refer to prices or costs.
at cost price at half-price at a discount at a premium at a profit
The firm also sells vitamins, beauty aids, and other drugstore goods at a discount.
The 2010 edition is still available at half-price.
This is a typical Berlin restaurant serving excellent food at reasonable prices.
These nouns are usually used with words that make the meaning more specific.
at ... cost /at a cost ... at ... expense at ... interest /at interest of ... at ... price