jmc

Clearly, the amount of money Ricardo has will be maximized when he has the maximum number of nickels. Since he must have at least one penny, the greatest number of nickels he can have is $2019$, giving a total of $(2019\cdot 5+1)$ cents. Analogously, the amount of money he has will be least when he has the greatest number of pennies; as he must have at least one nickel, the greatest number of pennies he can have is also $2019$, giving him a total of $(2019\cdot 1+5)$ cents. Hence the required difference is $$(2019\cdot 5+1)-(2019\cdot 1+5)=2019\cdot 4-4=4\cdot 2018=\boxed{\text{8072}}$$