Taxis:- These are everywhere. Drivers are honest, (but there may be one or two willing to over-bill you if you look, and act, like you do not have a clue). Taxis are good, safe, and are quite cheap. A short trip of a couple of kilometers will be around 300 pesetas. Going from Los Cristianos to Las Americas will be around 800 pesetas. A ride from Tenerife South Airport to Las Americas will be around 3000 pesetas. From Tenerife Norte Airport to Puerto de la Cruz it will cost approx. 3000 pesetas. Going from the Puerto de La Cruz to Los Cristianos, a trip of some 130 kilometers, will cost you 10 000 pesetas.
Taxis can also be hired for sightseeing. Just stop any good looking taxi and ask what they offer. Most offer pre-planned itineraries covering the main island sights. The price is around 13 000 pesetas for a half a day tour.
All taxis, (old, new, Mercedes, Renault, vans, car, limos), charge the same price... so it is advisable to always look for the best available car. You can pick the taxi of your choice even from the taxi line!

Ferries:- There are several ferries throughout Tenerife, from Los Cristianos you can travel across to La Gomera. The fares are around 4000 ptas for non residents each way. Schedules are available from travel shops and the terminals.