The vast majority of services offered by Student Health and Wellness are offered at no additional cost to students*. This does not mean that those services are "free" - students are assessed several fees each semester as part of their required tuition and fees. Payment of those fees grants access to various services on campus, including many of the services offered by Student Health and Wellness.
Some services are available to faculty and staff of Iowa State University, although those individuals may be required to pay a fee for access.
In general, "student" refers to an individual who is enrolled for classes during the current or upcoming semester and who does not have a hold on their university account.