DePalm Island is very nice. Nice beach, ok snorkelling, water toys and food available.
This trip can be fun.
If you want to do Aruba a bit cheaper take a bus out to the Palm Beach area (between Aruba Grand and Holiday Inn . Beach is wide and lovely and very public. There are facilities at the piers run by the three major tour companies De Palm, Red Sail and Pelican) for bathroom, food, drink etc. Plenty of vendors along the beach offer chair and water toy rentals and water sports opportunities.
We rented a Jeep right at the pier for $80 for the day. Navagating is easy and like the above poster you will see the island like no excursion will ever offer. If you do that make sure you check out "CONCHI" or the "Natural Pool". You will still have plenty of time to park your Jeep and check out Palm Beach on your own.