Doesn't make any difference in price. Most companies will meet you at either location but you'll probably (in my experience) be driven to their office to fill out all the paper work. If you're going to be in SP first then just open the phone book, go to the yellow pages and start calling around for the best rates. Personally I use Crystal and have never had a problem.
Price has to do with the fact that there is a limited market and that a huge duty is paid on vehicles coming into the country.
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