(This plant comes in a 3.5 inch pot. You will receive a very similar plant to the one in the picture. It may or may not be blooming at the time of your purchase. The plant is shipped in its pot to prevent any damage to the roots).
Rebutia vulpina is easy to grow and free flowering. Nevertheless.
Growth rate: It is a relatively rapidly growing species that will make large clumps given the best conditions.
Watering: Needs moderate to copious waterings in the summer (it is more demanding than other cactus), but do not overwater, keep dry in winter at a minimum temperature of 0°C.
Hardiness: It is quite frost resistant if kept dry.
Exposition: The plant tolerates bright situations which encourages flowering and heavy spine production but is likely to suffer from sun scorch or stunted growth if over exposed to direct sunlight during the hottest part of the day in summer. It grows well with filtered sunlight or afternoon shade.
Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz