I don't have one single kit that is comrehensive enough to be called a BOB. Rather i have a SYSTEM of kits. Maybe a GHB or EDC kit, plus several stashes here and there.

In every kit or bag, I have put cash in medium and small bills.
So, in every situation , I will be having cash in the portable kit/bag I am carrying plus cash in a kit nearby ( in car, office ..etc.)

Between any two kits ( mobile and stationary ) I may be having around $ 200. But this does not count what I have in my wallet which is usually medium and larger bills and it is usually around $ 1000.

BTW, I am not in the U.S.

Cash really solves problems that would otherwise make me frustrated. As a matter of fact, I have so far stubbornly refused bank advertisements and junk-mail SMS ..etc. to have their credit cards. I may go for debit cards though to purchase stuff from the U.S. Other than that, cash is both comfortable and suitable to my stressful lifestyle.