How could I put natural-looking waves in my hair? ?

I do not like to use hair products that I will be aware of once they are dry. My hair is too short to braid in a lot of parts. I don't want to spend money on a thermal waver or anything, but I have a natural wave pattern when my hair is wet. I comb it so that the part is correct, but my hair is straight. I like my hair, but I wanna change it up sometimes. Thanks. (: