I figured out the key to 100 billion+ - a few tips:
* There are 6 resources in the game: dice, stickers, money, rerolls, special abilities from current box levels, and special abilities from maxed-out boxes. All of them are important - especially the last.
* You want your FBI box to be laser-focused on boosting the scores of one or two squares.
* It helps not to be unlucky when generating the layout of the FBI box.
* Learn what the characters want and set up to be able to fulfill as many request types as possible - even heading blind out of a landlord.