Bus services are fairly unreliable on St. Lucia because buses do not run on a set schedule but rather when the bus is full, which can take up to 45 minutes. I tried getting to Soufriere by bus and took me almost 1 hr to get there plus 30 minutes walk to get to the beach. Better to hire a taxi as you will take you right to your destination and won't have to deal with waiting or walking.
best way to get around St. Lucia Yes, buses aren't really practical and taxis arent cheap. Renting a car is the best way to get around the island and see the sights like waterfalls, plantations, beaches, etc. Do rent a jeep because of the potholes.
use a local taxi operator I too would say to avoid the tours arranged by resorts which are ridiculously expensive and not an economical way to explore St Lucia. I agree car hire is cheap but not anymore than taxi. Make sure you use a local taxi operator to plan your own adventure which will be much more affordable.