I love buying cards on justcommons. They're my own virtual dime boxes and offer great shipping prices. Today, I received 300 cards I hand picked during the last months (I started adding 93 UD cards in May, I think).
Unlike Ebay or Comc, when I shop on justcommons, I have no idea what the cards look like. I'll usually use my carddatabase checklist, choose a few years (I'll focus on the 90s at first) and check to see if they have some Blue Jays I need. I try not to purchase cards that are over .30 cts, except for very high end commons that I know I won't find in lots or on Comc.
I won't bore you with my Blue Jays purchases (for now). I'd rather bore you with other sets that were included with my order :
93 UD inserts ! and one of the better looking ones. I'm now only missing 5 out of the 20 that comprise the set. And yeah, they chip easily because of the black border, but I don't really care about the condition of my cards, to tell the truth.
First, UD Masterpieces ! 2007 and 2008. I love that set (who doesn't ?). I tried finding complete sets at a decent price, but no luck there (especially when you factor in the shipping charges). So I just added cards randomly, not even looking at what they looked like on comc before. I'm crazy that way.
Ok, for 1973 Topps, I didn't buy them blindly. I looked on comc first and picked up whatever action shots I could find for cheap (less than .20cts I think). I'm happy with the result !
So there you go....I love blind trades so much that I'm even doing it with my own purchases...