Possible Clues:

• 'A' f-for agreement
• Goods bought on ____ may be returned if not satisfactory
• Without obligation to buy
• Informal British abbreviation of assent
• On which to test phone feature - return otherwise
• Was paperboy regularly selected for brief assessment?
• Chap producing contracts for acceptance, briefly
• On this there's no obligation to buy quintet of cheap provisions
• Form of sanction accepted by chap probably
• Publicity in a post office gets agreement