Echinopsis subdenudata "Dominos" is a globular cactus with white wooly areoles. It can produce beautiful large flowers. It is a very good beginner cactus.
Pictured in a 3" pot
Echinopsis chamaecereus or peanut cactus is an easily grown cactus. It is great for a hanging basket. It can have multiple flowers at a time during the spring and summer.
Pictured in a 3" pot
NOTE:
Echinopsis ‘Haku-jo Maru’ has a felt-like rib and fuzzy areoles that create interesting white lines down the cactus. It is a relatively fast growing cactus.
Pictured in a 2 1/4" pot