Was there in April and as Viajero Perpetuo said, VAT exemption is just for lodging. However, renting a car was surprisingly cheap there. I rented two cars in two cities, both for 4 days. One was from Avis (it was the only option available when I landed...) and the other a small local company (also the only option available to me). Both were ~$75 total, so don't worry too much about the VAT, etc.