Paradise Beach doesn't have an all-inclusive package that I am aware of. Also, no admission, but they ask that you spend at least $10. They also have a package where you can play on the water toys, have snorkel gear rental, etc. I think that is also $10. they do have a website.
By snorkel tours do you mean from the shore or from a boat?
Many of the beaches are free to cheap but you will still need a taxi to/from most decent ones. Taxis are relatively cheap.