When you get a domain it also has search engine value. Older domains have authority and backlinks. There are black hat and white hat considerations when doing this. It is black hat to buy a site about one subject and then make it about another. This will work for a time but is a short-term solution. Search engines will ban you at some point. It is white hat to buy a site that is about the same subject and keep the site on topic. This is a legit business practice and happens all the time. Companies buy each other out all the time and consolidate websites. What you are doing is buying a company and then making changes to the website.

drop shipping

Drop shipping is when you sell something before you even own it. Somebody buys it from you online and sends you the money. You then buy the item and they ship it directly to your customer. All you have to do is create auctions, take money, and order items.