Nepali currency is termed as Rupee. Rupees come in the form of bank paper note with Rs.1, 2, 5, 10, 25, 50, 100, 500 and 1000 inscribed on the notes. Nepali coins also come in 25 paisa, 50 paisa, 1 rupee, 5 rupee and 10 rupee coins. You can have your money exchanged at banks and hotels. Prior to any transaction, foremost inquire about the commission and charges that will be deducted for the money exchange at Nepal currency exchange rate. Banks are usually open from 10.00 am to 3.30 pm Sundays through Thursdays and from 10.00 am to 12.00 pm on Fridays. Saturdays are weekend holiday.
Credit Cards: all major cards are accepted for tourist services. There is usually a 5% mark-up on top of the price.
I have nothing more to add except to say its one of the most beautiful treks I have taken!