Purchased for my 5-6 year old at ~14usd to go along with an astronaut jumpsuit costume.  One size fits all.

THE GOOD: this really does fit all sizes from 5-105, including my 35 year man child of a husband...though his head is on the larger end and his nose gets a tad smushed.  Anyway, not an issue as it wasn't intended for him.  My 6 yr daughter loves it and she can flip the visor up and down easily.  Seeing as how this fits grown men, it does tend to shift around a lot, but that's understandable.  The decals are adhered well and I don't forsee them rubbing off at all.  It makes my kid happy!

THE BAD: this is cheaper end plastic and pretty lightweight which is also another contributory factor to why its shifts around so easily.  It's thick enough to keep it's shape so long as nobody sits on it or stands on it, etc.  It's thicker and better than cardboard, but don't expect anything like a motorcycle helmet.  It's 14 dollars...which is what I would expect to pay...would not pay more than 20usd unless it was crunch time at Christmas or birthday and nothing else was available.