Rogue Trader uses a "Profit Value" system, which treats wealth as another characteristic and to make a purchase you have to apply modifiers and make a percentile test against your PV. The point to this is that a Rogue Trader is usually so rich he doesn't need to count money.
In my campaign my Rogue Trader player is an extremely impoverished RT (he doesn't even have a Warrant of Trade yet, so it's fair to say that, ironically, he's not a Rogue Trader yet). Therefore, a Profit Value system doesn't make much sense at this point of the game.
I would like to use a money-based economy, that is, to give my players money for their achievements and they're free to spend it or save it. I would still use the "availability" tables, so they would or would not be able to find the item they're looking for, and then they would see if they have the money required to buy it. The problem is that RT has no price list for its items. Do FFG other books use a system similar to what I'm looking for? If not, how could I put a price to each item?
Bear in mind the biggest problem I have is setting the rewards for their "quests", because I don't know how much is too much or too few.