Goa in its unique location, a paradise for water sport lovers.If you are a single traveler than try the two wheeler taxis which is even more reasonable. The other option is to hire a two wheeler and explore the inner roads.
Goa is absolutely safe to drive and explore all the time.
Taxis are a great way to get around in Goa until you find your bearings.If you find a decent taxi driver you will tend to stick with him. And reward him with your custom.You may find that they have good info and work out cheap for your trips out.