First of all, you will need to download Android File Explorer and Subway Surfers Trick file
Now Open And Extract the Subway Surfer Tricks File and you will find a folder in it (Use Android File Explorer for This)
That Folder contains 3 files which provides unlimited coins and upgrades (COPY THIS FILES)
•From your file explorer, search for your already installed subway and go to Settings > Apps > Manage Apps > Subway Surfer’s and tap Clear Data.
•Use your file explorer to access
sdcard/Android/data/com.kiloo.subwaysurf/files/ on your memory card.
•You will find three files there, clear them and replace it with the one you copied from the Subway Surfer Trick File. Save and launch!.
Well easy Right there is an easier method which is through the link below, which will enable you generate the amount of keys you want.