I’m going to be frank and say that if you don’t know what the starred bit in the photo is for, then you’re not actually frugal.
What seems to have come with the new, post 1950s disposal economy is the willingness to throw “stuff” out because it isn’t as perfect as “the one in the picture”. Consequently supermarkets will only buy up the most ideally marketable fruit and veges, and not buy the rest. This leads to large amounts of waste at the farm or orchard gate in the name of “adding value” through quality control.
I know this from working for years in kiwifruit, where the tiniest blemish on a fruit can lead to it becoming a ‘reject’. There’s not actually anything wrong with the fruit it in question, it will still taste like crap the way all kiwifruit do, but it looks subjectively ‘odd’. I remember seeing bins of fruit being given away because it couldn’t be exported to Japan.
And that always pissed me off, because all they’re doing is inflating prices and limiting some consumers choices in order to make more money. Mind you, it means they transport less stock, but… they shouldn’t be transporting produce huge distances anyhow. It’s crazy to buy oranges from the USA when we grow perfectly good, though slightly ugly and harder to peel oranges here.
The wee appendage on the potato peeler is there to dig out the crappy bits of the spud that you don’t want to eat. Because it’s full of dirt for example. Or might be too hard to chew. Or might make the spud discolour when you cook it.
And why is that important? Because often the cheaper fruit and vegetables are the ones that are a little blemished, and if they sold more blemished fruit overall, then prices would be lower. What you want to do is deliberately choose the cheaper produce, but consider how much waste you’ll be digging out with that nobble. If the level of waste is too high, then you’re doing no-one any favours.
Mind you, I’m not recommending you never buy flash produce. Sometimes it’s exactly what you need for a meal like summer salads. But always consider what you can do with the crappier stuff, such as pickling, preserving, or stewing.