Coimbatore is a spread-out city. City buses cover most areas and are cheap. Auto-rickshaws are plentiful but negotiate the fare before getting in, as meters are rarely used. App-based taxis (Ola, Uber) are available and usually more straightforward for pricing.
For day trips to Ooty, Kodaikanal, and the Anamalai Tiger Reserve, buses from the main stand are frequent and inexpensive. The Nilgiri Mountain Railway departs from Mettupalayam, 40 km north of Coimbatore, for the spectacular ascent to Ooty.