When possible, gamers will tend to use the hardest item as money, SoJ in Diablo being the most famous example.

For a game to do this right, it’d need a fixed amount of currency to serve as money, but also a way to distribute it as fairly as possible in the beginning. 
Offering faction wide goals that’d give everyone whom participates a fair share of the money would be one of several good options.

Then let the free market handle the rest. 

Noobs would need to provide any kind of utility/services to the community to earn some money, or could be sponsored by friends pulling them into the game, like family works when you pull newborns into the world. 

Would be a great social experiment for sure.