A drawback is not an advantage. You should not profit simply for being a kleptomaniac. You are looking at things different from the developer's intent.
If it was simple to obtain 10 gp a day, it wouldnt be a drawback. And if the intent was to be a minor incovenience, it would be a small sum, like 1 gp, instead of an unrealistic value (for commoneers) like 10 gp. Remember that not all kleptomaniacs will be adventurers, and when trying to obtain their fix, they will likely get intro trouble.
Profession and downtime
If we look at the average profit from honest workers, like from the profession skill or using the downtime system, the character is looking at 1 or 2 gp a day of work. A character would need a +90 modifier on his profession skill to earn 10 gp a day using the downtime system for example. It's not impossible, but he would have to be the owner of sereval successful business to pull that off.
So, don't expect a buglar to obtain 10 gp a day casually, because he won't. The point of the drawback is to be an issue to the character. The klepto would need to pull several sucessfull crimes, like robbing the owner of several sucessfull business, in order to keep his drawback controlled.
If you, or the player, are not okay with that, consider replacing the drawback. Because you can totally be an addicted to pickpocketing without any drawbacks, but instead of robbing 10 gp a day, you are satisfied with 1-2 gp.
Or, instead of trying to obtain 10 gp a day, you could say that the character attempts a robbery every week and obtain the average of a week of work. At +10 skill bonus, that would mean 10 gp a week using the profession skill and taking-10 on your check. Instead of pickpocketing every day, he plans a new heist every week. He will suffer the penalties for a few days, but once he makes his skill check, those are reset to zero.
Heists
Finally, the last option is to plan a Heist. The heist does not need to be complex, or require all the player characters to participate, but must have a clear goal and the character has to do some legwork (knowledge/diplomacy checks) to figure out the location, security, logistics, etc. This will require a lot more work from the GM, as he will need to define what is available to be stolen, from whom, where, when the character can do it, and what kind of difficult he will face on his lone quest. But the heist rules will offer plenty of ideas so you both can work on it without much difficulty.
The Black Markets Player Companion book actually gives a example of simple heist that the GM can apply on this kind of situation:
One or more of your loyal teams infiltrate (see below) an organization or property to steal valuables or information.
You must spend 1 day of downtime and succeed at an Appraise or Sense Motive check (DC = 20 + settlement or black market’s Law modifier) to assemble the ideal recruits and provide them the necessary information on their target.
At any point in the next week, your assembled team or teams can perform their heist, attempting a check to earn capital as if performing skilled work. Because this capital is stolen from another organization, you do not need to pay the associated gp cost for earning capital. Assembled teams must succeed at a DC 20 check to earn capital, or else they fail and are reported or broken up.
Performing a heist to generate Magic capital imposes a –5 penalty on this check.
Regardless of the result, your target suspects your involvement. Blame can be deflected with a successful Bluff check, which may benefit from an alibi (above) or manipulating evidence.
To perform a heist without arousing too much suspicion, your team must first infiltrate it (see below).
The bolded part talks about earning capital, which is explained on the downtime rules. But basically you can earn something worth at least 20 gp using these heist mechanics. Which should be enough to please our kleptomaniac.
You spend 1 day of downtime to insert one of your teams into another organization to feed you information or steal resources. Doing so requires a successful Disguise or Bluff check against a DC of 20, modified by the settlement or black market’s Crime (for criminal organizations), Law (for law enforcement and military organizations), or Society (for governments and businesses) modifier.
While infiltrating another organization, your team can attempt checks to earn capital on your behalf, using any non-team bonuses provided by the infiltrated organization’s facilities and resources; you must still pay any associated cost for earning capital. Alternatively, your team can spend 1 day of downtime to attempt a check to earn capital and treat the result as a Diplomacy check to gather information regarding the organization, reporting the discoveries to you.
An infiltrating team remains ensconced for 1 week, plus 1 week if you succeeded at your initial check by 5 or more. You can perform the infiltrate activity up to once per week to maintain a team’s infiltration for extended periods. An infiltrating team can perform no other downtime activities on your behalf.
Instead of earning capital or gathering information, an infiltrating team can spend 1 day to perform a heist (see above). This ends the infiltration, but deflects any suspicion away from you or your organization; the target of the heist must succeed at a DC 20 Perception check (modified by the earning bonus your team used) to find any evidence of your involvement. Targets that fail their Perception checks by 5 or more don’t realize they were robbed.
A team of robbers should have an initial cost of about 200 gp to hire, train them, and earn their trust. But after that, they provide a +4 bonus on capital checks to earn money, goods or influence. A week of regular work (assuming you have no other bonuses on your capital check) should earn about 5-10 gp. This is not enough to fix the drawback, so the character will need to plan those heists regularly.
Settlement modifiers
Regardless of the chosen option, remember that the Settlement might have modifiers to the character's check, such as Crime and Law rating, which both affect pick picketing attempts and the security of the town in the form of guards and ease of robbery. The Economy modifier can be applied to profession checks to earn money, legally or not. The Society modifier can help the character on his disguise checks to infiltrate places. And the Lore modifier can be applied to all knowledge checks to research information and diplomacy checks to gather information. If everything fails, the Corruption modifier can help you bluff your way out of guards.
Character's reputation
You are also able to track the character's reputation within that settlement. Depending on what types of crimes he pulls off, this might earn a bad reputation with the city guards, but a good reputation with the crime organizations (such as the local thieves's guild).
To make it simple, you have 4 options:
- Have enough Profession (Pickpocket) (or another relevant profession) to earn 10 gp a day, or +90 to be able to take 10.
- Own several crime business that together can earn 10 gp a day, or +90 on the capital check to earn money.
- Take the penalties for several days, but pull a robbery per week. That way the penalties are gone for a day and will start increasing again while you adventure (but hey, you can rob your friends and reset it again).
- Plan a heist, which will take more time from the GM to plan the details so the character(s) can follow through their crime.