Ship classes.
There are multiple "classes" of ships in the Nova Wars Universe.
With the ability to "mine" gas giants and the plethora of minerals available in an asteriod belt, not to mention what high tech engineering can do, the problem is not with the raw materials cost, but rather the cost to manufacture them.
But, there are different classes.
Private Craft, excluding cargo vessels, rarely exceed the 500 foot length, varying from as small as 15m long, 10m wide, 5m thick to as large as 150m long and 50m wide. Private craft, for the most part, have limited shielding, light weaponry, low missile tubes, and only thrusters and moderate FTL drives. However, they usually weigh less than 250 tonnes.
Frieghters: These things can be the size of a normal picket boat (50m long, 10m wide, 4m thick) to larger than a Superheavy Devestator. A frieghter is usually lightly armored, lightly if at all weaponed, with weak sidewalls and limited shielding. They handle like pregnant whales and are sluggish as far as speed goes.
Light military ships: With decent armor, high power weaponry, hard thrust drives and thrusters, moderate sidewalls, well tubed, light military ships are larger than most private craft, requiring crew of anywhere from 2 men to 140.
"Ships of the Line": These are your big boys. Up to 10km long, 5km wide and 3km thick, with sidewalls able to brunt a supernova, shields to deflect a comet and weapons to destroy a planet, these ships are massive and crew in the thousands rather than the hundreds.
Any questions?