Just less money? Or something real?
Viewing post in CODENAME: Full Metal Heroes jam comments
After killing a 3 hostages, instead of a shop you'll end up somewhere else. There you'll get a debuff (e.g. loose health, loose ammo, no more medkit drops, ...).
However, you'll find a cursed weapon in this place as well. While they are stronger, you also receive more damage (another consequence) after picking up a cursed weapon.