for 300 cargo, plus alien tax, you are probably talking in the 300 range minimum, possibly 325-350 ish
Herc C2 was 300 warbond, 360 now.. Subtract 200 or so SCU of cargo, and you are probably looking at 250ish warbond at today's pricing (it's gotten really expensive) for a ship without alien tax.
My reasoning.
Valkyrie is 375. 330 initial warbond
Prowler, a lesser ship in almost every way, is 380 warbond and and 440 now
Prowler can ONLY land troops. Yes, it can fight a little, but the Valkyrie can fight a lot, can carry more troops, and can haul a vehicle or cargo. Prowler has stealth, Valkyrie has durability, so that balances. So, IMO, if the Valkyrie could only carry 16 troops and no cargo, it would be somewhere in the 275 range. This is supported by the Vanguard Hoplyte at 235, so 275 is a reasonable middle ground.