So... uh... the new shop has a massive exploit.
No gems to convert? Just make them out of thin air! Buy everything in no time! Want gems for figures? Make them by clicking the gems to tickets converter, then spend those tickets buying the gems back. You can even click the gem -> tickets converter before you hit trade by clicking it on the shelf to the right in the store.
I was debating on making a new save when the game officially launched, now I definitely will because I like doing things legit. Just had to see how far the bug went. Turns out "stealing the whole shop + figure collection" was the answer. Cassidy really was sleeping on the job here.