Ask your reference librarians for their list of magazines. Titles will be listed alphabetically. Be sure to note the years held at your library. Many medium and small public libraries circulate their magazines. This means that the issue you need may not be on the shelf.
Most people start by investigating local options.
This is the quickest and least expensive option. Your reference librarians can help you to identify local, regional and state-wide holdings. If your library doesn't have what you need, maybe a larger one does. Also, if you are doing work for a college course, you will probably find that many of the magazines you need will be at your school's library. You are welcome to use the materials in all public and most academic libraries.