I don't know the prices of the big joints but my advice is to get quotes from various travel operators, including the windsurf travel ops.
Car rentals abound too.
Should anybody ask, you are going to learn to windsurf. Local People and Tourists Local Folks, at a first glance, look kind of scary. They reminded me of people from unsavory neighborhoods of the city I live in. They are very courteous and serviceable to the tourist though, they will give you exactly what you ask them, they won't rob you, and you are safe walking at night in Aruba. Tourists are for the most part on packages, mostly from the States, Holland, Scandinavian countries, Austria, Switzerland.