Taxis aren't metered, and a fare is agreed on with the driver before departure.
The minimum fare is ST$3, and a fare from Faleolo International Airport to Apia should cost ST$60-70 - payable in cash (tala). Around town, fares range from ST$3-12 cash.
Given Samoans’ low income and the high cost to repair vehicles, many drivers drive very slowly, especially when the road is rough. Give yourself plenty of time to get anywhere.