In the USA there are at least tens of thousands of people who supplement their wages or even make their whole living from buying and reselling. Some go around to early morning garage sales usually held on Saturday and buy anything they think they can resale for a profit. Some go around to flea markets and do the same. Flea markets are locations permanently set up on a large commercial property like an outdoor shopping mall, but those selling are usually selling used items gathered at garage sales, other flea markets, etc. On eBay there are many thousands of store fronts that mostly sell used items the owner has acquired from people wanting quick cash. So there is a huge culture of buying used items in the USA from people you really don't know. Some probably sell these Kindles without even knowing how to operate them. They are wheeler-dealers, but unlike the British car show of the same name these people probably don't know much about the used items they sale.