What should I use on my dry brittle hair?

My hair is thin and I color it,straighten it out, and I also go to the pool.I need to fix my hair because it keeps breaking off easily and it feels so dry.I get a trim every 2 months but that doesnt seem to help.Any suggestions would help but I need something affordable and I don't mind the expensive suggestions but I don't know if I will have the money to get it done!! Any suggestions will be greatly appreciated