Get in contact with @bsgkid117 he is the guru for 3D printed hulls. They vary depending on what size ship you want.
Invincible is a beginner boat, the cost is almost entirely in how long the boat is not necessarily anything else. Even my French Suffren class cruiser kit, which is ideal for a new captain, is $175. It's cheaper to ultimately build because there's fewer cannons and there's only one drive motor, but the cost to produce the hull and everything is almost the same. Keep in mind, my price includes: Hull Deck Superstructure Turrets Prop shafts + props Drag discs Rudders Misc hardware like rudder drive gears and such.
@Benicio Lopez , that HMS Invincible is exactly the kind of ship I was talking about in our PM. Not the slowest but not huge and complicated. These guys have been working on the 3D prints for a while and the boats are solid. The Suffren would be a good starting cruiser too. Simple to build.