SIM cards were readily available at many places, from the UTS offices to the Mailbox to the small groceries and Tech Hub (inside Carrefour grocery). Prices (20-$30) will vary and should include 10 minutes or so on the card. Make sure you have an unlocked phone.
UTS StoresTECH HUBDriving is pretty easy, just pay attention and watch others as turns can happen any time and any place and you will see people stopping to talk to other drivers, which can back things up some.