American Airlines have low one-way airfares travelling from Philadelphia (PHL) to Memphis (MEM) for $47, nonstop. If you could build a round-trip airfare with the dates below, it'd be $88, nonstop. See my screenshot for a RT airfare. This is a basic economy fare. After Sept 5th, American will allow one carry-on, in addition to the small personal item, on board for free.
Frontier Airlines have this airfare at $70 but Frontier will only allow 1 small personal item and that's it.