Someone (but I can't remember who) has a signature where they are looking for black beans for less than 99 cents a lb. I haven't been able to do better than that locally for a while, but today I found that Target.com sells black beans for 89 cents a pound, free shipping on $35 or more, and an extra 5% off with Red Card, so 85 cents a pound. If you're near a Target store, there's also an additional 5% off Market Pantry dried beans until tomorrow.
Garbanzos and brown lentils are the same price, and pintos are $1.59 for 2 lbs.