Glyn;
As it has been mentioned, weapon cost is not a very big part of the total ship cost.
Engines and all of the one-off components like ECM/Sensors/bridge are a huge chunk of change, particularily on small ships in stock.
And also, if your weapons are cheap but large and weak, you'll need to sacrifice shields/armor/engines in order to get the same firepower.
Or build more ships, and pay a hefty fine in the build cost of your bridge/lifesupport/crewquarters/engines/sensors/etc
Be careful not to misplace the dollars while you pinch your pennies!
