Weapon trading

[MANFACE!]

You trade with drugs, why not weapons too? You could buy metal pieces and wooden pieces aswell as screws to assemble guns at stations, same for ammo which you create at ammo stations with metal pieces, gunpowder and lead.

Of course that would also require the addition of weapons and maybe also special police units to come at you when you use these weapons so they won't make you too OP.