I know they are not very expensive, I have never opened any of the sets they came in.
I bought a collection I am nearly done sorting and there were a lot of the SH shiny cards in it, in conditions that should bring psa 9 when I Send them in.
I think the SH cards are way more common. I’ve never opened a booster box of Platinum sets but I used to pull many shinies from the packs that I opened. I think they used to be one per box or something. Gold Stars used to be 1 in 2 boxes