Wow, you actually need a business license for something like this? Anyways, this probably won't be a very reliable source of income (as you already knew). You would probably develop an addiction to checking craigslist and ebay every half hour. Karma wise, I would probably say no. But as the saying goes "The early bird gets the worm" [or $200 dollars in your case].

[edit: had to fix my typo!]