If you want to keep costs to a minimum ECARO-25 is the most cost-effective chemical agent fire suppression system in terms of agent cost per pound.
Because water and inert gas are naturally existing chemicals that we obtain from the environment and capture for use in fire suppression, they are the greenest solutions available. With a global warming potential (GWP) of one, FK-5-1-12 is the most ecologically friendly of the chemical agents.
For two main reasons, inert gas systems offer maximum flexibility in configuration. These gases are stored at pressures greater than 4,000 psi, as opposed to chemical agents, which are stored at pressures ranging from 360-725 psi; and they are stored as a gas, as opposed to chemical agents, which are stored as a liquid.  Liquids incur huge friction losses as they circulate through a piping system.