@taylor1awesome: it's not that hard to get, I have 8 billion. The only problem is that there is no possible way to buy a level 500 newspaper stand or even car wash. It would take at least a month or two
@highih, I always go for either double the number I already had or 10 times. If it's your first time however you could just reset when you are struggling to upgrade stuff.
 "AdVenture Capitalist"){kind=icon}
 "Backyard Monsters (removed)"){kind=icon}
And another one!