The ad above (from Mobile Centrix) links to a video explaining "Grade A, B, and C" of "Blemish Screens". Grade A has just some bad pixels (like you'd take your phone back to the shop you bought it from yesterday, dissatisfied, for replacement). Grade B has "bleed" discoloration at the edges. Grade C has visible chip-out black spots on the edges and corners.
A Rich Person's Broken Thing (Chapter of Adam Minter's Secondhand, after an explanation from my Grandpa Clarence Fisher) is the smartest thing a poor person can buy. I've seen absolutely cake-smashed screens in everyday use in Africa.... no one is without a smart phone, but no one is paying $250 for screen repair, either. Instead, they buy these from their cousins who run the kiosk for phone repairs out of your local shopping mall.