This Gymonocalycium marquezii will ship to you bare root, but will be very similar to the small pictured plant.
Size - G. marquezii is a smaller clumping cactus. It makes for a great desk cactus.
Sun - Full Sun, some shade
Water - allow soil to dry out between waterings
Cold Hardiness - 25 to 32F - I never let mine get below 40F.