To check them on eBay directly, you can go to the advanced search, then search for the exact card, including set and number, then filter results to Sold items
Cactuars 7 mana cost does keep it respectful, but in these days of fast mana and cheating creatures out, its not a stretch to imagine this card being a winning move out of nowhere
Join the party with the Pokmon TCG: Celebrations expansion!
If the cards people like most are those that are top down rather than bottom up then perhaps it is a good idea to design a cube with that method taking the lead
Not only that, it has flashback, enabling you to cast it if it gets milled, or to get two Elementals out if you're able to cast it from your hand and grave
For someone running their first Pokmon bot setup, this is the starting point