It's a Rhododendron - this particular kind was previously classified as Azalea. As for precisely which, I can't be sure - the leaves are wet, so I can't tell whether they're naturally glossy or leathery, and the flowers are not yet open, so I can't tell from the size of those either. There are two types of this plant which look quite similar, and sold at this time of year - Rhododendron obtusum is hardy outdoors down to -15C, the other, Rhododendron simsii, is not suitable for planting outside and is usually bought as a temporary houseplant and kept indoors. Rhododendron simsii, the Indian azalea, has leathery leaves, larger flowers and once they're open, they cover almost the entire bush, whereas R. obtusum has flowers which are half the size and glossy leaves.
If it turns out to be the hardy one that can be planted outdoors, they need fertile, rich, acidic soil in part shade - they do okay in full sun, but can't cope with soil that dries out, so partial shade is usually best. They flower for about 4-6 weeks, in spring, and don't flower again till the following year.