When looking for a rental car in Playa del Carmen you will finde out that renting a compact car (like Toyota Yaris) is the cheapest at 7 days. If you can exchange the car within a 14 days period it will even be a lot cheaper prices from begin December 2016):
5 days: 14,03€/day (70,13€)
6 days: 14,03€/day (84,16€)
7 days: 7,84€/day (54,85€)
8 days: 9,01€/day (72,11€)
9 days: 9,93€/day (89,37€)
10 days: 10,66€/day (106,64€)
11 days: 11,26€/day (123,90€)
We had a very good experience with Mex rent-a-car in Playa and and a very bad one with the same company in Cancún airport (they wanted to sell some SLI insurance for 200 USD/week and didn’t want to hand out the car. Told us it would me mandatory for now – all other clients heard the same bullshit. After 45 minutes of discussion and calling the office in Playa they finally gave in…