As recently as last year there were still niches where spelling errors led to arbitrage opportunities: I knew someone who was into CCGs (e.g. Pokémon, Magic: th

As recently as last year there were still niches where spelling errors led to arbitrage opportunities: I knew someone who was into CCGs (e.g. Pokémon, Magic: the Gathering) and would search for variations on card names, score cards cheaply, and keep them around to trade at full value later. Same rationale (which I agree with!): eBay gives you a way to say "I will not accept a price less than $N" and a way to say "I will accept the highest bid regardless of magnitude." Trying to second-guess a seller's choice between those is just totally not viable.