you need 30k rep whihc comes wiht the heart access in order to form a platoon (aka gang) and buy a base. It also gives access to the hi tech merchant who has not only the best stock, including miniguns and rocket launcher, but also spawns all the conditional bags of each zone. Each zone you control spawns more caps on every merchant as wellas enables a special bag on that very merchant, who also sells everything at a noticable discount, though he accepts only caps.
You also get access to the doctor to buy class a+b drugs and the advanced doc and fa kits and there is antoehr random assignment giver to higher difficulties