Change main.dat extension to .zip open the zip file and open Grant.lua in that file you can modify the amount of money grants give.
And you can also modify the price of materials , objects and staff by modifying materials.txt and material_new.txt

I unzipped main.dat last night to see what files were accessible. There's the material files and been able to modify the price of objects I'm trying to find what controls the timer at wich get the prisoners arrival. There's also the objects tilesets. Haven't played too much with the files yet Can't ...