There are several options for purchasing iron fillings, wire, and magnets. One option is to visit a local hardware store or home improvement store. These types of stores typically carry a variety of materials and tools, including iron fillings, wire, and magnets. Another option is to check with a science supply store or educational supply store, as they may also carry these items. Online retailers such as Amazon or specialty science websites may also have a wide selection of iron fillings, wire, and magnets available for purchase. It's always a good idea to compare prices and read reviews before making a purchase to ensure you are getting the best quality products at a reasonable price.