The Giant near the 22nd trolley stop is really good. It's the 'regular' version of the store, not the Heirloom version on 8th. Their chicken breast is almost always $2.49 a pound which is the cheapest I've ever seen it. Sometimes it even goes to pre inflation $1.99 too. They're also really good about rotating stock so you can often get the 50% off meat as long as you freeze or cook it relatively soon.