Hi Cathy,
You'll be able to find something to suit most budgets - when I travel I budget as if I'm dining in the UK and this tends to cover the meals. I do recall a post on the community awhile ago stating that the traveller found it quite cheap: www.justyou.co.uk/forum/thread-57355.html
The Nuevo Sol is the local currency but you will find that US Dollars are also in use and accepted for payment, particularly in tourist areas although it is best to use local currency wherever possible.
Kindest regards
Julia