Prickly pear grows outdoors in all but the coldest parts of the United States. As a house plant it needs lots and lots of sun. Put it in your sunniest window or supplement with a fluorescent table lamp if needed. Water only when soil is dry a few inches down and less in the winter.
I tend to over pot cactus so I don’t have to transplant them often. If you do this you have to be especially careful to avoid over watering the plant.
Also remember cactus really don’t need fertilizer. Skip it, but if you must, then use an extremely weak solution rarely.
Prickly pear is used as a food source as well. Down here in Houston you find it in the vegetable section with the thorns removed. I have not yet tried it. The fruit from the flowers can be made into a jelly, the pads are used as a vegetable.
Irish Mittens Cactus