The best website I have found for getting reduced price salon hair products is www.wantthelook.com They also offer loyalty points as well!
My hair is badly damaged due to too much straightening and although I have used salon exclusive products for a while now (I definitely find a significant difference between them and shop bought ones), I personally like Schwarzkopf and have found that their Cashmere range for 'Stressed hair' is proving to be excellent for my damaged hair and the difference is obvious already! They do a shampoo, conditioner, a deep conditioning treatment and a serum.
You may find that the prices are a lot higher than shop bought products but because you are able to use so much less of the products, they actually work out to be similar in price really!