Frailea tenuissima Family: Cactaceae. A small clumping cactus species (but large for a Frailea) with white spines and yellow flowers. Takes normal cactus care but can be sensitive to overwatering in winter. Protect from frost.
You may notice some black dots in the images or on the plant you receive. Those are seeds. Feel free to plant them!
You will receive one of the plants shown in the last image or one similar. They are shown growing in a 4" pot.