Panteen. I like it, it cleans well, doesn't build up & doesn't cost a fortune. I think shampoo isn't quite as important as the conditioner. That is something that you want to get right for your hair type. I use Nexxus Humectress because you can use it as a daily leave in and as a deep conditioner. It lasts a very long time.
Styling products are another place to put your $$$. But again, I do not think you need to break the bank for those either. Be smart about what you buy, read the ingredients. They are all about the same, so there is no reason that one should cost $40 and another $ 10. They are going to be about the same... you are paying for the name, not the ingredients.
Joico K-pack reconstructing shampoo and conditioner. It leaves my hair looking healthy and shiny so I like it. I like to switch out my shampoos and conditioners because I like that variety to choose from.