This is the standard connector, found on one end of almost every USB cable. It's a rectangular connector that only fits in one way.
You'll find several USB-A ports on virtually every desktop computer and laptop. Many TVs, game systems, cars, media players, and other devices have one or more, too.
You won't find a cable with USB-A on both ends, because there really isn't any situation where this might be useful. In fact, connecting two computers with a USB-A cable may damage them