I'm so old, I remember when you could go to Gold Circle and buy a blister pack of Yo-Yo strings in the toy section.
That is also why I learned to switch price tags; because, the Egyptian strings were twice as much as the cheap American made ones. And, well, I'm a criminal.
@Sempf You can still buy them on Amazon and other places.
@AAKL What, yo-yo strings? Well sure but go look at a contemporary toy store. Even better, ask staff where the yo-yo strings are. You will probably be escorted out in a straightjacket.