Easy and tough! The Desert Candle cactus (acruensis Euphorbia), also known as the 'cowboy cactus' is the plant that you think of when you think of the word 'cactus'. Yet this plant is not officially a cactus, but a member of the spurge family. Just like the real cactus, the Euphorbia can store a lot of water and therefore does not need much. This makes the plant easy to look after. A great choice for every plant lover! 
The Euphorbia tolerates light well, but can also be placed somewhere with less light. The less light the plant gets, the less water it uses. Give it extra water on a monthly basis through the summer. The plant will need less water in the winter months.
For the greenest of living rooms!