We've never rented anything at Princess Cays since all we want to do is relax at a shady location next to the water.
As far a anything they provide free it's a chair or hammock and a free lunch which isn't to bad. Hamburgers, hot dogs, b-b-q chicken, chicken breast with fruits & salads. They also have a limited dessert items like brownies & cookies with ice tea available but no lemonade. I think they also have hot coffee although I've never looked for any.
I usually rent a float for $8.00 a day. Grab a lounge chair, read, swim, and then float around - easy to fall asleep on a float in the sunshine! There's usually an impromptu volley ball game going on. Nice live music.
Lunch is a good old picnic lunch - all good.
It's a very relaxing way to spend a day in the Caribbean.