Make Auric Cells Giftable In-Game
Simple, allow, in post game wrap-up (and maybe in other ways), an opportunity to gift auric cells to other players. If you're worried about shady things (hopefully it's already implemented in a way where you can't inflate how much you have), you can limit to only 1 or 2 per game. But, over time, players who can't buy the cells can build up enough to get something exclusive with it.
Seriously, the devs still make money no matter whether the cells were individually purchased by the people who use them, and this way they'll make even more... because there are always going to be people who will buy some just to so they have them to give out from respect to people who played a great game, or to apologize for running some kind of toxic build they wanted to try out, or because they're streamers and it's part of their shtick. It may not happen often, but even the possibility of it will encourage less toxic behavior in general, because... I mean, if you were going to gift someone some aurics for a game but they start being toxic in the end-game chat, you're probably not going to, so at least a few people might restrain themselves.