Hey! I had the exact same issue, and dandruff shampoos barely helped at all (and usually smelled awful to me.) I started washing my hair with baking soda, tea tree oil, and water—my scalp gets squeaky clean now! Plus my hair texture has improved tenfold as a bonus.
I have a blog post with before and after pics, if you're interested in reading: My “No ‘Poo” Experience « [Work In Progress]
You can also use lavender in place of the tea tree oil, if you dislike the smell of tea tree oil.