My local costco sells breasts for 2.99 / lb for 12 breasts. It is really nice b/c these are already separated into bags with 2 breasts per bag. All 6 bags are connected with perforations between them, so when I get home I separate the bags and throw some in the freezer and keep some out for my week's cooking.
I am sure there is a slight cost for this convenience, but it is worth it to me, and 2.99 is a pretty good price for these things.