Did you really think arbitrage of used goods could be a business? I think the best thing these types of experiments do is expose pain points and inefficiencies that you can make businesses out of. When I was in my ramen phase of startup life (and newly married), I used to (among other things) buy clothes at local thrift stores and resell them on eBay for a decent margin. You quickly learn what brands/items sell and o…
In the used clothes example you are either limited by time (I can only hit ten thrift stores in a week) or supply (there are only ten thrift stores in my area.) After that, how do you scale up?