TOO BIG TO FAIL: To mark the anniversary of its one millionth order, Net-a-porter is giving away a $40,000 shopping spree to one winner chosen at random. Anyone can register once; a purchase is not required. “We said, it’s got to be a fabulous over-the-top number,” said Net-a-porter vice president of sales and marketing Alison Loehnis. To put the number in perspective, it equals a capsule Balmain wardrobe, 160 pairs of jeans or a pair of Christian Louboutin shoes every day for two months, she said. The contest starts Thursday and runs for three weeks. It will be advertised through e-mail and social media.