"Meaningful" is going to be very different from person to person. Even $10 would be discouraging to so, so many people, while some people on here wouldn't balk even at three or even four digits.

But the TIME you lose on a high-level character, that stings for EVERYONE. I don't think you need to raise the stakes even further. Like, why, what are you even gaining? The goal of the mode has already been met.