Best shampoo and conditioner for oily hair/itchy scalp?

I'm looking for a good shampoo and conditioner to use. I currently use Tresemme but my hair gets oily so fast and my scalp is constantly itchy. I've always had good luck with Aveda but it costs an am and a leg to buy, although it does usually last me an entire year if I buy the big bottles. But I'm looking for more suggestions.