In the free market, anything goes. In the domain market, there's a finite space within which we have to work in. If you want to buy a domain at a ( 250/8 = 31.25 ) 3100% markup, so be it.
Well, how much do you value your time, per hour? And how much time does it take you, on average, to find a decent .com domain name and a decent temporary logo? You don't seem to include that in your calculation - unless your time is free, or you're really amazing at finding domain names. In which case, you could be making a mint.