I guess the reason why it seems confusing is because if you're prioritizing risk/reward tradeoffs and saying that spending the money for good data is worth it t

I guess the reason why it seems confusing is because if you're prioritizing risk/reward tradeoffs and saying that spending the money for good data is worth it to you, why not license the data from a reputable source? That said, I think I might not have conveyed my original question well enough - what I actually meant was 1) is the data accurate? (you sort of answered this by saying you compare it to presumably licensed sources) and 2) what actually led you to searching for financial data on ebay? (you didn't answer this, other than "it's cheap"). I'm basically wondering how you did the mental calculus that concluded ebay was a good place to check before you verified the data was alright.