The following are house rules regarding income outside of adventuring for the Feorri Sector Campaign.
Professions and Crafts
Having a Profession skill grants one a fairly broad grasp of knowledge areas related to the performing of a particular occupation -- areas, that is, not specifically covered by other skills that already exist. Crafts allow a character to actually manufacture items. Both of these skills have the additional benefit of providing a source of income between adventures.
Since I do not plan on working out the activities of every character from week to week in between adventures, I plan to utilize these skills in the following way:
Immediately before every adventuring session, any character with a Profession or Craft may roll the appropriate skill to determine a week's worth of income. This does not necessarily mean that exactly a week has passed between adventures, nor does it mean that this represents all of the money the character has earned. It is an abstraction that represents what extra spending money the character will have, after working at a regular job, and paying various monthly expenses (which may change now and then, hence the randomness). Since this is not a roll done under stress, the player may opt to use the "Take 10" rule, rather than rolling dice for this.
In the case of any character who actually has a means of income (such as a Profession or Craft), I do not assume that the amount of money written down on the character sheet represents the extent of that character's money, and that all his worldly possessions are written down on his inventory list. For one thing, I don't expect players to write down every article of clothing, but rather just those articles that have some particular effect on game play (such as an All-Temperature Cloak, or Power Armor).
The character might well have an apartment or even a home back on some planet, maybe a personal landspeeder, a holo-entertainment system, several changes of clothes, and so forth. The character's specific inventory list and in-game funds represent what items and funds are important to the game -- whatever items the PC brings along that might have a bearing on things, and an abstract representation of how much money he can afford to spend.
This does not mean that a player who really wants armor and weapons can ask the GM if he can sell off his house, his landspeeder, his entertainment system, his pet vornskyr and all his extra changes of clothes so he can get more credits. That's not roleplay. That's "mix-maxing". If your character is the sort who would sell off everything for a bigger gun, then assume that he already has ... and broke it already. The player characters all start out on equal footing. You don't get freebies for choosing to play your character as a total ascetic who lives only for shooting things. Nobody else is going to be able to get any benefit during the game out of a landspeeder or a holoentertainment system "back home", anyway.
We may not necessarily use the rules listed in the core rulesbook for crafting items. They're unwieldy, and lead to very strange results in certain circumstances. If your character wants to build things, then the GM will invoke uses of the Craft skill as appropriate. As a rule of thumb, if you've got the right Craft skill, then in between sessions, you can build a given item if you can beat the given DC for the complexity of the item, and spend one third the cost in raw materials. The GM determines what modifiers apply (such as availability of materials, supplies, and tools), and how long it would take ... and, consequently, whether you'd have time to do it.