I was trying to change rewards amount for each mob. For example, I have this in my config.yml:

# ### Pig settings ###
  pig:
    enabled: true
    message: You killed a §1{killed}
    money:
      amount: '2'
      chance: 1.0
    commands:
    - chance: '0.05'
      cmd: give {player} Iron_ingot 1
    head:
      drophead: true
      value: '0'
      chance: 0.05
      message: §aThe §1{killed} §adropped a skull on the ground

with amount "2", but, when I kill a pig, I always get $10. I restarted server 3 times.
This is just an example, because this happens for every mob.
I don't know what is this caused by, I activated debug mode and seems that nothing went wrong.
I also have McMMO, MythicMobs and EliteMobs, and I configured the last two in their own config files in the MobHunting folder.
I also deactivated Bag of Golds, because I use TheNewEconomy and Vault as currency plugin.
What can I do?

Try enabling debug mode

/mh debug

And then kill a mob and check the server console.

I have never tried with TheNewEconomy this could be the problem as well. But if it is Vault complaint it should work.

Hm... TheNewEconomy said that Vault is optional, so I don't know
I tried with debug mode, but nothing looks like an error... it should work, I think

[01:17:35] [Server thread/INFO]: [MobHunting][Debug] MythicMobSpawnEvent: MythicMobType=WraithServant
[01:17:35] [Server thread/INFO]: [MobHunting][Debug] MythicMobSpawnEvent: MythicMobType=Orcling
[01:17:35] [Server thread/INFO]: [MobHunting][Debug] MythicMobSpawnEvent: MythicMobType=OrcKnight
[01:17:35] [Server thread/INFO]: [MobHunting][Debug] MythicMobSpawnEvent: MythicMobType=WraithWarrior
[01:17:51] [Server thread/INFO]: [MobHunting][Debug] ======================== New kill ==========================
[01:17:51] [Server thread/INFO]: [MobHunting][Debug] DanielVip3 killed a Pig (Minecraft)@(world:189,63,-25)
[01:17:51] [Server thread/INFO]: [MobHunting][Debug] KillAllowed: Mob killed by DanielVip3 was allowed by WorldGuard
[01:17:51] [Server thread/INFO]: [MobHunting][Debug] Permission 'mobhunting.mobs.*' or 'mobhunting.mobs.PIG' not set, defaulting to True.
[01:17:51] [Server thread/INFO]: [MobHunting][Debug] KillBlocked PIG(2449): Mob has MH:blocked meta (probably spawned from a mob spawner, an egg or a egg-dispenser )
[01:17:51] [Server thread/INFO]: [MobHunting][Debug] ======================= kill ended (26)======================

Edit: I tried replacing TheNewEconomy with AConomy(but didn't work). I also tried Essentials Economy and Fe, and they both don't even get money when a mob is killed.

Check this line

[MobHunting][Debug] KillBlocked PIG(2449): Mob has MH:blocked meta (probably spawned from a mob spawner, an egg or a egg-dispenser )

You don't get money for mobs you have spawned with eggs, but you can use the essentials spawnmob command.