Yes. Its name is Mexican peso (Spanish: peso Mexicano)
It always changes. Go to xe.com
$1 USD = 3.7 Peso leys (ARL) = 3.7 Neuvo Pesos (ARS).
Go to OANDA.com then FX history and set dates required
If you mean a peso it's not worth cashing in but some banks can convert it to pennies if it's enough.
The Peso sign is placed before the amount.
after
I'm going to go ahead and assume you meant to write "currency". If you did As of today(6-20-12) the Dominican Peso or DOP is $39.00 for $1 US dollar.
If you go to Mexico, you can spend Canadian dollars at a 10x1 conversion rate (ten Pesos equal one Canadian dollar). The actual conversion rate is about 12x1, but it changes fairly frequently. You can look it up on a site like xe.com.
http://coinmill.com
Philippines is right. Like, "Do you want to go to the Philippines?":)
Most people go to Lucky Plaza. but I think it worth checking other spots. You will find them at www.get4x.com which well tells the rates of different money changers in Singapore. after that it is up to you to choose!