I used a house rule to determine how much one skill could help with another.
I don't know how familiar you are with the later rule sets, but I do remember that the Combined Action rule was refined a few times. Today, I don't remember exactly how it was used, but second edition revised & expanded had a pretty good rule for it--I remember thinking at the time.
I also used abstract rolls for wealth, though hard numbers ended up to work better.
I've heard that the new Star Wars game by Fantasy Flight uses a die code for wealth. That wouldn't be too hard at all to translate into the D6 game. It's kind of a neat idea.
Each character would have a Wealth statistic. 1D would represent minimum wealth, if the character has anything at all. Something like 6D or 8D would mean that the character is very wealthy.
Then, items to buy simply have difficulties assigned to them. Something inexpensive, like a new pair of boots, might have a Difficuty of 3, or 7, or maybe even 10. The GM can adjust the difficulty to account for item options and quality--and also scarcity. Supply and Demand is a simple matter of picking a Difficulty number for an item. The price of a starship might have a difficulty of 30 or more.
I'm just making this up as I write. You'd have to refine the idea. But, how it works is: Let's say a character needs a new pair of boots. The GM says that a cheap pair is Diff 3. A regular quality pair is Diff 7. And, a high quality pair with reinforced toe is Diff 10.
The character simply throws his Wealth code, and if he achieves the number or higher, he buys the item. If he fails the roll, then he doesn't have enough money.
You could even use the Bargain skill with this, maybe adding a character's Bargain skill to his Wealth code.
So, let's say a character has Bargain 4D (decent at bargaining) and a wealth code of 1D (broke). The character throws 5D when attempting to purchase an item.
Just like in real life, though, not everything can be bargained. So, maybe, on some items, Bargain can't be used--just the wealth code. Other items might have a limit to the amount of Bargain that can be used: Maybe something with a little give will allow only 1D of Bargain to be combined with the character's wealth code.
It's a real interesting idea. And, it has the added benefit that it requires no bookkeeping, the way keeping track of money does.
These days I'm thinking about using fuel and consumables as dice ratings that get reduced like damage vs. STR rolls, because I don't want to track days of fuel/food/air/water etc. I should put some thought into that, though.
You know, they also took the consumables out of the 2nd edition game. I have both the 1st edition and 2nd edition supplement on Tramp Freighters. The first has a system for starship supplies, like life support, battery back-ups, etc. The second edition book completely throws all that out in favor of fast and furious play.
If you wanted, you could also use some kind of dice code system for this, too.
