Copping Multiple Pairs

Hi. I was wondering how some people get like 5 pairs of a shoe on release day. On social media, I see people with like 5 pairs (sometimes even more) and they start selling them for a profit. For example, I saw someone with 7 pairs of the Carmine's, and he was selling them for $280 shipped. 

HOW DO PEOPLE GET THAT MANY PAIRS!?!?!??!