Rebecca - Dave's reply was missing an answer to your question: "Everybody that receives it buys Acrobat 8"? No, those using the forms DO NOT need to have Acrobat Professional 8. Usually one person (such as yourself), has Acrobat 8 and enables the rights on those forms created (there is actually a selection to do this). Once the form is enabled, anyone who simply has Reader can fill in and save a form.
Hope this helps!