With a backpack slung over his shoulder, Jacek Kryg walks down one row and then another of outdoor vegetable stands at Warsaw's historic Hala Mirowska market.
The 72-year-old Kryg already knows which one has the best prices on carrots, broccoli, mushrooms and his other staples.
But he is keenly aware of what he spends, so he double-checks all the prices.