Hi Ashley -- You dont' really need a lot of expensive equipment to engage students in science investigations. There's a lot you can do with hand lenses (studying rocks, insects, leaves, etc.), toy cars and ramps (motion, friction), string for pendulums, blocks, paper or plastic cups to grow seeds, a hand-made journal for writing, modeling clay. Take a look at the articles in Science and Children, and you'll see many specific activities that use materials you may already have or that you can find in a dollar store if your school can't purchase them.
The Frugal Science Teacher is an NSTA publication with selected articles from Science and Children that use simple materials. I'd recommend it. See also the blog No budget or low budget science.