hi there,
First of all, I'd say to familiarized yourself with the currency once you get there, so you are able to bargain around, specially in the street markets. Second, check out the nearest cash point in case you need to withdraw money straight away.
Port of Spain is the best place to
shop in Trinidad and
Tobago that include arcade malls on Frederick, Henry, and Charlotte streets, or you can consider heading to the Brian Lara Promenade and get some art craft and purchase local goods.
Hope this helps
Vacationbuddy