You will need to install a user script manager extension to install this script.
This is to be used with TamperMonkey and it's tested working on Edge and Google Chrome.
Make sure you use this page https://play.google.com/store
How to use: Enter a fake 16 character code. The 4th character is the most important part.
Example: XXX[0-5] XXX XXX XXX
Any character besides numbers 0-5 = $25
Lets say I use this code: ADF3 FEWF LQPO FEW2. The result will be $300
Or lets say I use this: 0ER5 032F GFDS GRE2. The result will be $500