If you have a sunny, south-facing window in your home or apartment, try growing indoor cactus. Indoor cactus are easy. Many grow slowly over time, don't require frequent watering and tolerate our dry, indoor air conditions in winter. Use cactus potting soil, and water throughly, but infrequently, and don't mist the plants. It's good to choose the right cactus. While all cactus are considered succulents, not all succulents are cactus. Cactus have growth points or areoles where spines, hairs and flowers grow. Here are some of the easiest cactus to grow in your sunny spot.
Angel Wings cactus is related to prickly pear cactus. It has hairs, not spines, on its pads so it's easier to handle. It grows slowly to 2 feet tall and with enough sun, it will send out yellow flowers in spring.
For a nice hanging basket houseplant try the rat tail cactus. This is a fast growing cactus that can trail 3 feet long. In a sunny spot it will produce bright pink flowers in spring.
The Old Lady cactus is a classic, round, 10-inch tall sphere that's covered with white hairs. But don't grab it because there are prickly spines in those hairs. It forms a ring of small, pink flowers.
While the African Milk Tree is technically a succulent, I add it here because it's so easy. I got a cutting from my brother years ago and it rooted easily and is still growing strong. It grows straight up, with branches that continue growing vertically, with reddish-purple leaves. Just watch out because it can grow 4 feet tall or more, even indoors.