Ranging from comfortable vans to pick-up trucks with narrow wooden benches, aluguers provide connections between even relatively small towns on most islands. They pick up people at unmarked points around town, set off when they're more or less full, and drop passengers off anywhere on the way, on request.
Taxis are generally plentiful, with round-town fares rarely topping CVE500.
Airport runs and excursions are more costly.
Hitching is easy, though payment is sometimes expected. It's usually safe, but be aware of the possible risks.