Yes it is a gamble buying anything raw and even worse when scan is blurry.I just bought a OJ Simpson rookie last month for $18,scan was hard to see but looked centered, it just came back an 8. I got lucky on that one but got screwed alot more on others,tiny creases,trimmed,stains,bad corners ect.I still buy some raw cards but just don't pay too much for them.
Wanna sell it and triple your money? 
Hey, you can't get that kind of return in the market.
But I agree it can be a crap shoot. You'll get a few nice surprises, you'll get your share of disappointments.
If the seller offers a return policy, you really can't lose too much though - a few dollars shipping and some time.
