Regarding Makes:

Cars made for Costa Rica and other Latin American countries are different than their US counterparts. For example in the Nissan line, they offer a Platina, Almera and Primera - none of which are available in the US. Diesel engines are more common than the US (heck, you can’t buy a new diesel vehicle in California!) because diesel is cheaper and more economical. You will find practically every kind of car here but finding a good car can be very difficult.

Toyota and Nissan, in my opinion, are the best but also the most expensive. Mitsubishi is OK but the ones made for outside the US are of a lower quality than the models shipped to the US. My personal opinion is that all Suzuki, Geo, and any Korean made vehicles should be avoided.

Think Ahead - Spare Parts
If you buy an American vehicle, anything from Europe like Peugeot, Renault, Fiat, or the lesser common Japanese cars like Subaru, Acura, Volkswagen, Lexus Honda, etc. don't plan on being able to find any readily available parts for it outside of the San Jose area.

My advice is to rent a car for a month and look at as many as you can. The rental agencies charge $200 - $500 per week. If you are lucky, you might meet someone like me that has a few cars to sell and will make a deal to use one of them while you are looking for one to buy.