Money in Nicaragua
In Nicaragua the official currency is the Cordoba, which at this time is at 27.5 Cordoba to the US Dollar (or just under four cents per Cordoba.) This is not the easiest conversion to have to do day to day. Nearly everything in the country works on Cordoba. In tourist areas it is extremely common to find US currency in use and even some restaurants or hotels with prices listed in USD. Street beggars and street sellers nearly always ask for US money since they almost universally target Americans. Sometimes you will hear them asking for pesos if they mistake you for Mexicans.
ATMs in Nicaragua will generally dispense either Cordoba or USD. Cordoba are written either as C$ or as the two characters merged officially but few character sets have that character so C$ is more common.
Cordoba come in coins of C$.50, C$1 and C$5. Paper cash comes in C$10, C$20, C$50, C$100, C$200 and C$500 denominations. ATMs typically only dispense C$500 notes.
That means that the largest note that you will see in Cordoba is worth just over $18.
Many places in Nicaragua do not take credit cards so be prepared to have cash on you at all times. Most places will take credit cards, but certainly not all.
Chip and pin cards are just coming to Nicaragua now in 2015, so while you see these advertised heavily you do not see many in practice yet.