Hilton Head Outfitters. 20$ seemed to be some kind of winter special.
The food was great! We paid 25$ each for lunch (appetizer+entree+iced tea including tax and tip). Not so bad. But again have a look at the buffet before ordering that. It did not look good but was the cheapest option. We instead ordered from the menu based on what people were having at the next table

Ask to be seated on 3rd floor. Much nicer and quieter than 1st floor. Also the staff is really friendly and helpful. We'd go back for sure! My wife knew Paula, I did not have a clue who she was before visiting Savannah. She's everywhere! She has her own store but you'll find her stuff all over town.
We did not get to go as they want 3 people min and we were only two wanting to go. But we saw plenty of dolphins from the beach!
Hilton Head Outfitters also rents kayaks. The resort does not, they only offer kayak tours, so most of the times the kayaks are just sitting there. Too bad.