You’re half right. And you could be entitled to a refund. Under the city’s hotly debated bag bylaw, retailers of all kinds—not just grocers—are obliged to charge at least five cents for each plastic bag. Rare exceptions include bags for dry cleaning, bacteria-busting bags for meat or poultry and plastic bags at the pharmacy counter (because disguising one’s Viagra prescription is a God-given right). The rules for paper bags are more complicated. In most cases, store owners can technically charge whatever they want for a paper bag. They could charge you $20, though presumably you’d have the sense to tell them where to stick said pricey sack. The only exception under the new bag bylaw states that if a store can’t provide a five-cent plastic bag, paper bags or boxes must be free. To determine if your store committed a punish­able offence, we’d have to know if there was a plastic alternative. Chances are the clerk who took your nickel was simply making a rookie mistake, but if the “fancy store” was really desperate enough to make an illegal five-cent cash grab, the economy will almost certainly exact your revenge in the near future.

• Question from Tara Roberts, Summerhill