I really doubt that "sweetening the pot" is banned considering that WB put in a substantial pot for MK9 in 2012. Unless policies changed since then.
I found this on some random
E sports site... don't know how legit this actually is:
Evolution 2013
Jul 12th, 2013 to Jul 14th, 2013
Evo 2013 (SSFIV:AE) - $16,370.00
Evo 2013 (Ultimate Marvel vs Capcom 3)- $13,020.00
Evo 2013 (Super Smash Bros. Melee) - $6,960.00
Evo 2013 (Injustice: Gods Among Us) - $5,820.00
Evo 2013 (Street Fighter X Tekken) - $5,730.00
Evo 2013 (King of Fighters XIII) - $4,270.00
Evo 2013 (Persona 4 Arena) - $4,000.00
Evo 2013 (Tekken Tag Tournament 2) - $3,550.00
Evo 2013 (Mortal Kombat 9) - $2,330.00
EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE Sports.
We in there.