I'm not 100% sure on this but since the price of the item/ship is also info, I think if you go into the mods folder and search up the correct ship you should find all its info there and be able to adjust it.
Maquis|Leon.LaBreau-If your interested in joining the Maquis PM me. [RM]Of.Viktor.Niklovach[RoS]GhostFace[E]David.DeWester[101st] Order|Ens.Adam.Jones[C]Jean.Claude.Moreau Kruger Security-Johann Von Struger]bd[Akio.Kimura
You can use IONCROSS char editor. Save you the trouble. Less work and saves you from editing any Freelancer files.
Edit your ship, money, powerplant, guns, engines, cargo, lots.
1) Go to Data/Equipment/Goods.ini
2) Ctrl+f search for re_hull
3) change 'price = 172000' to 'price = 0'
Note, this is just the cost of the hull, you still have to pay for the internal equipment. It'll still cost you 30k and I'm not familiar with reducing the cost of internal equipment, but you can always up the payout of missions so you can buy the ship if you don't have enough still.
What Sky Jocky said.
Just search for the name of the ship in the goods.ini file in the equipment folder. Should be there. Some are named strangely so patience is advised.
Remember to keep it off the server though:PThe server eats you if you try it anyway.