We all did it as kids, looking briefly, it doesn’t make you go blind
But a cheaper way to get real protection is just to hold a piece of plate glass at the end of a candle flame, and let it get coated with carbon soot ... makes a great sun filter!
Sounds sketchy. An arc welding filter will work, I forget the exact grade. 14 I think. But if you let your pupils fully constrict (opposite of dilate) instead of just suddenly looking at the naked sun, it won’t do a lot of damage to look right at it. I’ve heard of people that have permanent spots in their vision from looking at the sun, however. So doing it is stupid especially since there’s no real reason to.