Rented from Margarita/Isis this past October = $45/day for 12 days - inc all ins, newer small car w/ AC. If you don't use the car for 1 day it's bye-bye $45. Times 2 = $$ for 1 dive day. Versus taking a taxi it can be quite an expense over time. I like walking and am not a fan of driving (or parking) in MX, but my travel companion was adamant. On the other hand it was easy to go to the east side, visit the Humane Society, get to a beach club and venture back in the hood with a car. Still, if it were just up to me I'd rent for a day or 2 for those far flung places and then walk/taxi the rest.