Discount Riddle...

Man walks into his local Tesco on a Friday after work...

...and he's delighted to see that a 4-pack of Stella is reduced by a quid - normally £5.50 now £4.50!

'Get in!' he mutters to himself, pleased as punch.

...he then heads to the pub and drops £100 with his mates.

Is getting a discount really about saving money?