Opuntia violacea, var. "Santa Rita" is often called Purple Prickly Pear.
This option is for pads over 5 inches straight across, and have been growing 3 to 5 years, sometimes longer. These are landscape quality pads, (which means that the cutting which will become the base of the plant) may have cosmetic blemishes, also called scarring, which is usually caused by other pads rubbing as the plant grows)
At this size, pads are quite heavy, but are excellent for creating a stable, strong base.