The game you will need is Scatter Slots. This guide will show you how to get infinite gold, gems, and power ups for your scatter slots. Please note, that this only will work as long as you still have the Halloween event open. This will work for other holidays as well.
1) Click on "Go" on the Halloween section to go to the Halloween bonus area.
2) Escape out by hitting the home button on your phone. Make sure you are still on the Halloween bonus area when you do this. Go to Settings > General > Date & Time and uncheck "Set Automatically"
3) Change the time of your phone to some point in the past. For example, change the time to July 1st, 2016
4) Using the home button, open the Scatter Slots app once again. If done correctly, you should see a ridiculous amount of time remaining, like "Time Left: 2967:40:30".
5) Chose the Free Pack, and flip all the cards.
6: Hit "great" and you will see that there is one day remaining before you can do it again. Staying on the Halloween bonus screen, hit the home button again and change your date one day ahead (so July 2nd in this example.)
7) You will notice that it says "Collect" again, You may now do this each "day" from July until the 31st of October.
By doing this, you will get infinite gold, gems, and power ups for scatter slots. In addition to that, you will also receive days of VIP. Currently I have 671 days of VIP remaining! If you collect all 10 monsters you get a 5 billion gold bonus.
Hope this helps, happy Halloween!