1. Open up 'File Explorer' in Windows
2. Goto 'Documents'
3. Goto 'iGrowGame'
4. Goto '<Your Save file name>
5. Open file 'details.txt'

You should now see an open text file with something 'similar' enclosed:

username=[your encrypted username];
money=[your encrypted funds];
level=0;
xp=0;
rooms=0;

copy paste this value into [money=T42GQ5T.D2;] with out the [ ].

Also, now is the time to change your level if you want. (level number is not encrypted so if you want to be level 60, replace 0 with 60)

Save file and close. You do not want to make this file read only!!