If you do not need an isolate, I would go with a blend, like mentioned above. Blends are better than just straight whey or casein alone. Some good options are:
PES Select
MAN Clean Protein
USP Lab Modern Protein
You could also go with a whey blend, this will be cheaper than a whey and casein blend.
Cellucor Cor Whey
AI Sports Whey
Animal Whey
I would go with any of those options over a bulk powder. Bulk powders tend to not taste as good. Either they are poorly flavored or the flavoring is weak. I would rather spend the extra money and get something I would enjoy eating/drinking. Also, look at the protein content per scoop.