There are a few instances in the rules where you are able to spend cash or mark down how much you have to spend at a given time and even bribing local cops. 

My three questions are: 

• Is there a guide for how much money is reasonable here, or should we just model it off what we know about today's currency, account for a bit of inflation and maybe the old tropes of certain things being more expensive for certain groups? 
• Is there a way to determine how much jobs pay like with a sliding difficulty rating. 
  • Ex: a campaign with 15 jobs(3 per location) could each have level 1, 2, and 3 jobs increasing in difficulty and pay, but might be for late game stuff.
• Is there a guide for deciding how much each person starts off with, especially Insiders who may have wealthy family vs Outsiders living in MSZ?

This is an issue that I became aware of as soon as I published the game, but I've never gone back to it to correct it. There's no good answer for your questions, from me at least, but I hope that others have addressed this issue and can help you out. If I ever return to ttrpgs, an update to Mutants will include solutions to this problem.