I've been considering switching actually. I need to find one which doesn't make my hands feel weird though. To ease my conscience a bit, I've been buying larger "lower plastic" refills for the smaller bottles.

I tried a bar shampoo but it made my scalp itchy and my hairs felt like they were coated with a "sticky soap film" like in the old Zest commercials

Being poor isn't the only reason to use the whole bottle though