Casas de Cambios are money (currency) exchange houses or booths, located at airports, and near shopping or tourist areas.  A Casa de Cambio will ex-change your travelers checks or cash to pesos at rates slightly lower than what you could receive at a bank.  They are convenient though as they are open after the banks close and do not have the long line-ups banks do.  There are Casas de Cambios located in Barra de Navidad, Melaque and Cihuatlán.

When exchanging money, it pays to shop around as the exchange rates often varies between Casas de Cambios.  Know what the bank rate is before you use a Casa de Cambio.  That way, you'll know what your losses or gains are.  Some charge commissions, so be sure to ask.

Always have your passport and identification ready before going up to the tellers window, and only sign and date your travelers checks in the tellers presence.

After the teller hands you money, always take the time to count it in front of the teller before the next person steps up to the window (caja).  If you walk away and later find a discrepancy, you will have no recourse for correction.  Always ask for small bills, as small stores can not change large ones.