What is a good drugstore product to make straight hair curly/wavy?

I have thin, straight hair that barely does anything when I try to scrunch it up. It just makes it crunchy feeling. I use the Herbal Essences Tousle Me Softly mousse and doesn't do much for me. Can anyone recommend some hair products whether its mousse, gel, or a spray that will help scrunch and make my hair wavy? Any suggestions on how to scrunch it also?