duty free or not?

How do the prices at the duty frree shops at the airport , say for rum or kahlua, compare to purchasing them at a grocery store in town? And should I hang onto some U.S. dollars to pay for them if at the duty free? Thanks

I find buying my rum or vodka at a liquor store in PV is much cheaper than buying at the duty free.

we usually find our Kaluha, some vodkas, etc.. cheaper at the airport... but if you want some good deals on Jamaican rum head for the Super La Playa... i usually spend about $200 US there.. i exchange first and pay in pesos... but i go home with my Jamaican rum and Don Julio tequila.... as well as some mezcal with the worm to show off at the bar... LOL but check out the Super La Playas and check them out.. each one is independently owned so you could find a good price at one and not so good at another... LOL