Not sure if this is the right place to post.. I notice some kind of cover was missing from my 2013 prius c 2 and I am trying to find a replacement.. right front. Its about 4x4 square and i see the white Styrofoam of the bumper and a hole. Tried to upload pics but the site will not let me.
If it is the tow eye cover, there should a threaded hole in the frame inside. And there should be an eyebolt with matching threads stored with the spare tire or jack handle.
search eBay or salvage yards. they might even be cheap at an online toyota dealer, but you may have to paint we have found with 7 toyotas that small plastic bits are always falling off. i'm not impressed with there connector engineering.
Have you been to an automated carwash lately? They might have yours. Even if not, good place to check, they might have some. It's item #7 here, pretty cheap: Bumper & Components - Front for 2013 Toyota Prius C | Toyota Parts