Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Phuket City to Tampa as you normally would.
Related info for your journey
Useful info, stats and facts about Phuket City to Tampa flights.
These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a Phuket City Airport to Tampa Airport flight would often be abbreviated as a HKT to TPA flight.