Undyne asks how sans gets money to pay the big house.So the sentry job doesnt pay enough, maybe neither undyne's royal captain job pays enough for that Paps says its a mystery. Paps may know or not I think its sans judge job that makes him afford enough (besides some money sans gets with his other jobs of hot dog seller and so on) What u think? Did asgore employed sans has the judge and it pays so well? Or is sans kinda "self" employed as judge? Hows sans getting the money for the big house?
Nothing in game supports the idea that being “the judge” is a job for Sans. Not only is there no mention of any “judge” position, but the position really doesn’t make sense for anyone but Frisk. Judging Frisk before they meet Asgore is to steer Frisk in the right direction, considering Frisk’s actions “will determine the fate of the entire world.” It’s unlikely that Asgore pays Sans to do this, especially with how few humans have fallen down in the underground.
So what jobs does Sans have? First, he is a sentry, and he has four stations. This is actually something Undyne is not aware of.
Although Undyne is Papyrus’ boss, and thus should be Sans’ boss as well, this doesn’t necessarily mean she is in charge of the hiring or paychecks.
Second, Sans sells hot dogs at his “illegal” hot dog stand.
Third, Sans performs at the MTT Resort restaurant.
There’s no way to know exactly how much money he makes off all these jobs, but it’s clear he has many jobs to support himself and Papyrus.