Nice experience with Cabrera car rental, which has three points of sales: SJU - Carolina, Rio Grande and Fajardo (major spots east side of Puerto Rico).
I discovered Cabrera through a general purpose renter: Rentalcargroup.
There exist many website that offer you the best rates comparing the major and sometimes some local car rentals, so they are a good option, but need advance reservation and get cancellation fees.
In Boston I find Autoeurope is among the cheapest ones.
In Puerto Rico they have agreements and discount rates with Cabrera. They claim an instant rental confirmation upon reservation. Instead it took me two/three days to have confirmation, because they still need to manually contact Cabrera. And sometime Cabrera may refuse a reservation if it is too low and they are receiving many requests. If this happens, after waiting two or three days, you might get much higher rates or not find your desired car (and it can happen with 7-seat cars).
I choose Rentalcargroup because they were slightly cheaper or had the same price as Cabrera, but I thought that through Rentalcargroup I had less chances to be cheated, by a small local rental car.
Instead Cabrera has been very serious and reliable. Their vehicles are new, clean and they have been courteous and prompt.
I had a low rate on cars (compare with other prices below) and only payed 50$ drop off, which is a lot less than a taxi ride between SJU and Rio Grande. In addition they offer a free ride to/from hotel or airport (and they also took me from a private home).
End July beginning of August 2011 I was looking for a 7-seat car (minivan) for three days more than one week ahead.
These are the prices that I found from various car rentals (I may have been unable to find the information, so this may be wrong or not complete):
- Avis had no minivan. A large 5-seat car was 300$
- Enterprise was 320$ at SJU airport and 400$ at San Juan, but could not find a rental car in Rio Grande. Later I discovered that they have an office at the Wyndham hotel at the Rio Mar resort where I was heading to
- Autoeurope was 380$ with insurance included (which I do not needed), but it was unclear about drop off fees and and pickup
- Cabrera costed me the 300$ + 50$ for the drop off
- Rentalgroup was same price 300$ + 50$ , and they take 15% as anticipation for themselves
- Budget in Puerto Rico is only present at the main SJU airport and does not carry minivans
- Sixt in Puerto Rico is also only present at the main SJU airport
- Alamo National also are not present in Rio Grande and did not have minivans available.
- Vias, a serious local rental car, is not in Rio Grande, but they were only 270$
- Popular is also not available in Rio Grande, but it is widespread on the island as it is a branch of Banco Popular. It had the best price, only 230$ for a 7-seat car for three days
