It's funny how the devaluation of the Jamaican Dollar (105:1 is just crazy) made small bills less of a problem for me this trip.
I brought $60 in singles and brought some home, and I took plenty of $5 bills too.
Unless you are spending a LOT of money, US and JD were pretty interchangeable this trip. Not as much of a savings by always paying in J$.
Of course, local cook shops, bars etc are the exception and J$ is the best for paying there.