Sneakiness at the Grocery Store

I went to the grocery store for canola oil, among other things. I found three name brand products on the shelf, all suitable to me. The prices were all different and the bottles initially appeared to be the same size. Instead of just grabbing the cheapest, for some reason I stopped and examined all three brands. I discovered that the highest-priced product contained 48 fl. oz. and the other two contained 40 fl. oz. Dividing that out to the price per fluid ounce, the canola oil in the larger bottle was less expensive. That got me to wondering whether someone with poor eyesight would notice the difference between a zero and an eight, given that all the bottles were very close to the same size. You other grocery shoppers out there probably know that the price per ounce is usually printed on a tag on the grocery shelf, so you don't have to do the math yourself. The information on the tag would also be hard to read if your vision was faulty. Those of you who know me will now better understand why I began categorizing marketing lies separately.