they have booths at most of the card conventions and trade shows
If you want a clean copy that you can grade, it will cost serious cash, with LP sales posted at $500 while an NM card sold for $1,2000, leaving plenty of upside for this Mew.
In contrast, "Soul of the Supreme King" is the complete reverse of this, which can Special Summon "Z-ARC" without using any materials (though its effects are negated) but it can banish "Z-ARC" to Special Summon monsters from the four archetypes
However, this cards cuteness goes beyond just Sylveons cute-filled aura: the entire design from the cards pink glow, to the charming stuffies lining Sylveons bedroom just screams cuteness
This is one of very few cards on this list that isn't graded PSA 10 - and since a copy has never been sold in PSA 10 condition, it's hard to know if they exist at all