However, we popped in on Saturday, clutching a free voucher from one of the national newspapers. It entitled us to a bottle of Green King London real ale, valued at £1.79p.
The voucher clearly stated it was only valid at participating Tesco stores, and a search of the shelves at the Brigg outlet soon showed that ours didn't have any bottles of this brand in stock.
We were going to leave it there, and go home empty-handed, when a very helpful member of the store management stepped in and said he would still honour the voucher if we'd like to select a similar ale, which we did.
He even accompanied us to the till as another member of staff processed our free pint at one of the checkouts.
Every little helps, Tesco says in its slogan.
Later, we raised a glass in agreement.
Five stars duly awarded for customer service!