In Lima, I recommend taxis because they are plentiful and relatively inexpensive. As with other cities in Peru, tell the driver where you’re going and agree on a price before you get in. Lima is a giant city, so taxis from the airport to Miraflores can run s/50-s/80. Taxis within a neighborhood cost s/10-s/30.

There are buses in Lima, but unless you know the city well, they are difficult to use because each bus line is separate; they are not an integrated system.

Here’s a useful blog about getting around Lima.

Safety

Theft is a major problem in Lima, so always keep your belongings close and when you’re in a cab put them on the floor between your feet. The US Embassy recommends always using rideshare apps or asking your hotel to call for a safe taxi. Personally, I’ve never had an issue with taxis I pick up on the street in Lima.