The last time I went to the grosherie store looking for buttermilk, I had two choices: 1 quart for $2.49 or a half gallon for $2.79. Guess which one I bought?
After that, any recipe that originally called for milk, called for buttermilk. I had buttermilk panckes and waffles, I had buttermilk cakes, I had buttermilk biscuits, I had buttermilk macaroni & cheese... and yes, I managed to use it all up before the expiration date! Which is good, because I have no idea what bad buttermilk looks, smells, or tastes like.