I've had way more luck in the shampoo department. I went to Lush on Newbury at the start of the semester and blindly asked the saleswoman for advice. I knew I wanted a solid shampoo to cut down on the bottle waste, but I didn't know which kind to choose.
When I told her my hair was thin and needed volume, she suggested Seanik, made with seaweed and sea salt.

Then she told me I could get a free tin case if I bought two, so I coughed up $20 for Seanik, the tin and Soak and Float, which uses cade oil and lavender to cure dry scalps.

I used the Seanik first, which ended up being a total fail. I kept it in its tin but in the shower, and somehow water got in and turned the round bar into liquid really quickly. That was hard to actually get out and onto my hair, so the $10 shampoo bar went down the drain in a month or two.
Lesson learned, I kept the next bar, Soak and Float, in the medicine cabinet, and all was well. Just a little rub against your hair and it lathers up a ton, so I think this one will last a long time. Plus, this anti-dandruff shampoo is wayyy better than Head and Shoulders.
So even though Lush shampoo is pretty pricey compared to, say, Trader Joe's $3 biodegradable liquid shampoo, Lush nixes the plastic bottle, works better and will probably last longer. The only con is the earthy smell... but I've still kept my Suave Ocean Breeze conditioner. Baby steps.