The last day of the Penny

As of today the Canadian mint are stopping the pennies that are in circulation and are not producing any more as it costs 1.6cents to make a 1cent coin. If you pay by cash the shop will either round up or down to the nearest 5cents, but if you pay by card it remains the exact value. We've been wondering how much you could save by paying cash for values ending in 1 or 2 and paying by card for values ending in 3 or 4 cents. Every penny counts ?