I have two ATM's and wish I didn't buy them since you can get as many slot machines paid with money as you want. I currently have 21 slot machines (spent 2.1 million to get) which makes money much faster than I probably will need once I have everything the way I want it. I also bought five werewolves, two the champs, and four yokozunas. Although the tips are better with the werewolf, I don't need the extra money due to the slot machines. The champs are great for killing the fastest, but their lower health makes them want to die more often (even with my level 10 one that has 335 energy). Yokozunas are the best just because of the amount of energy that they have. They are great at serving (will never get a 10 dollar tip like the werewolves) and cooking for long periods, and can beat other zombies up quite nicely. I also have 6 of the fast cooking stoves which helps a lot with cooking for others. I have Frankenstein for his high health (for if someone raids me… even though I block everyone in for energy conservation reasons) and tip multiplier which is nice. I highly, highly recommend the toxin barrels though, as I have six of them. They do not heal the zombies at the 10% rate that is stated, in fact it's more tricky than that. The average zombie heals one energy in 20 seconds. With one toxin barrel that number goes down to about 10 seconds. Two will bring it to just over 5 seconds. Three drops it to 4.2, four is 3.7, five is 3.2, six is 2.6 seconds. So even though 6 only drops it by about half, when refilling a 705 energy Yokozuna, it only will take 30 minutes instead of an hour to fully refill. It's worth it if you have the extra toxin. Toxin is actually easier to come by than this site relays. You can win up to three toxin in certain fights (unknown until you beat them), and can get the bonus ones that are given for daily cooking, which decreases the number of days needed every time it cycles (i.e. on each subsequent cycle).