What kinds of materials do I need to have in order to provide inquiry-based hands-on science for my students?

Actually, you don't need as much as you might think. The average budget allotted to teachers for materials is 10 cents per child, per day. The activities in this site reflect this by making use of inexpensive everyday materials that, in most cases, are already at your school, or are considered basic school supplies, or can be found at most grocery stores, or can be found in your curbside recycling bin.