A couple months ago, my apartment complex changed how they treat the water and it's become a lot softer, which has resulted in my hair not getting as clean.  I often find myself feeling like there is shampoo still in my hair, despite rinsing it pretty well.  I don't have a lot of extra money to be spending on hair products that cost more than $10 but hate that my hair feels so gross.  Are there any products out there or other remedies that can help me that won't break the bank?

I have medium long, thick hair, if that helps.