k

You can exchange your pounds for pesos at any cambio in Cancun. Rates will
vary slightly, but it's not worth the effort to find the 'best' exchange.
You'll earn pennies at best, surely not enough to make a search worthwhile.
That said, hotels are not likely to give you the best rate.

You will need pesos, there's no doubt, but like others have said, you'll do
best with your credit card where you can use it. However, you'll want cash
for purchases from vendors, and for things like an ice cream, or a
newspaper, or a cab ride.

We normally exchange either $US20 or 40 at a time depending on our immediate
plans, and just get more pesos when we're low. Coins are the hardest things
to hang onto, and are also the most useful for tips and such. Those you can
get from a hotel cashier.

Keith