Do you have an online shop?

My friend recently opened a online shop, sell toys, I'm not sure when she started, just found out today. On-line shops nowdays are very popular, friends around me buy frequently, cause it's cheaper and conveient. But making the shop a bestselling one is not an easy thing, there's a lot to learn. Do you have an online shop? Do you buy things on line, what do you buy the most if you buy on line?