Yes, once you are on the beach you usually would have access to both paid and unpaid amenities. 

All location offer different options, So it will depend on which beach you are planning to visit.

Your rental typically includes a high-quality beach chair and a sturdy umbrella for sun protection. Some locations may also offer additional amenities at an additional cost

Most of the rentals are for the entire day. But longer periods can be arranged.

No, but depending on the location towels maybe available for sale.

Yes, one must be over 18 years of age.

Yes, it depends on the beach and it would be at an additional cost.