Nothing set in stone so far. It would have to be a sum that hurt to lose for most people, but also one that wasn't too large. Regardless, if not other conditions were constructed, a person with a lot of money could buy their way in.

Thankfully, there already are other conditions in the proposed system and the real losses would in most cases be higher than the initial sum thanks to player initiated "life staking" in game, which would produce both psychological and economic attachments the loss of which would be capable of acting as yet another deterrent for both current and potential players.

Hopefully, if we can design it well, sabotaging the game results in enough both money and opportunity lost that it would seem unattractive for the most part.