You do not need to invest money, like @niallon11 said.
But there is quite a difference between SM and DRUGWARS.
You can make money from steem monsters due to the market and players determining value.
This game is NOT like that.
Drug wars is essentially a pyramid scheme if you look at it as an investment. So you shouldnt look at it like that. Thats the biggest problem i see now. Folks that were late for Steem monsters think this will make them money. This is another beast completely.
You should see it as a game that redistributes part of the spent money back to the players... But only a part.

Its a game, you can play it for free, but only put in money because you enjoy the game, not because you expect a ROI.