Car Rental or Not

If you are spending a week or 10 days in Merida I don't think you need or want to have a car for the entire period.  With in Merida it's easier to take a taxi as the street system and maps are very confusing outside of the historic center where everything is logically numbered on a grid.  A day trip of 8 hours with an English speaking guide will cost you about $120-$150 usd and you'll get where you want faster with no arguments over wrong turns and missed photo ops.   If you are driving to Merida from Cancun then it might make sense to rent a car if you are more than two people as the bus fares R/T would be about $100 each.  There are rental car scams (mostly in Cancun) which can be avoided altogether by choosing an international company like Hertz or Avis and taking all of the insurance options.  But if you arrive in Merida I think it's easier to take a taxi from the airport.  Our english speaking driver can pick you up with the keys to the house on arrival and he will pick you up at 5.15 for that dreadful early morning return on United to Houston for the same price as a taxi $150-200 pesos.  If you are going to rent a car I would recommend doing so for a couple of days in the middle of your stay keeping in mind that the best days to walk around centro are Saturday and Sunday as there are fewer cars and buses.  Sunday is the biciruta bike ride through the city and there are pedestrian streets from Santa Lucia park to the Zocalo with crafts and food booths from the villages.    Here is a list of car rental companies and they all have locations at the airport and in or near centro.