The Metrobus system covers most of the city (fare $2.25). Maps and schedules are online and in the visitor center. Bus 3 is useful; it circles town via Military Rd and Water St before heading to the university. The new 'trolley line' (it's actually a bus) loops around the main tourist sights, including Signal Hill. It costs $5/20 per person/family per day.
Car & Motorcycle
The city's one-way streets and unique intersections can be confounding. Thankfully, citizens are incredibly patient. The parking meters that line Water and Duckworth Sts cost $1.50 per hour. Sonco Parking Garage is central, but there are several others; most charge around $2 per hour.
Except for the trip from the airport, all taxis operate on meters. A trip within town should cost around $8. Jiffy Cabs provides dependable service.