Sorry bugambilia's, wrong choice of word using "tons".
I would never carry a large amount of cash on me when on vacation.
I just meant back in 93' american money was used more than peso's when we were in Cancun, therefore using lots of small bills vs. using 20's or larger US bills.

I've read people saying us US money when buying items as the people of Mexico get a better exchange rate yet I've read where people say use only peso's. Thus wondering which is best to us, peso's or american dollars.

I'm leaning towards bringing both with us ~
Thank you.