*In the tutorial area of the first street you have infinite: Life / Ammo / grenades, in this guide i'll show you how to farm a bit exploring this.
*Harder difficulties means more zombies wich means more $

1- Let me show you were the tutorial area ends:
* you can see that the area ends in the trader door, so don't pass or even be close enough to this point or you'll have to restart or progress in the game

2- Atract the max of zombies you can.

3- you don't need to be scared of damage, you're invencible in this area.

4- Bash zombies to open a way out to you and then flood grenades on them.

5- Repeat the process (you can go back and forward the street to bring zombies [still don't cross the trader door line])

6- Staying close to the trader line will make zombies come eventually

~Edknox