I generally like to pick out pristine condition items/animals. I take excellent care of my property, so my stuff tends to look almost the same on day 1,000as it looked on day 1.
In regards to a snake with a scar, if it were a snake I really wanted, and the price was right [for me] to begin with, I could look past the scar and buy the snake. However, if there were other snakes quite like it and quite similarly priced, I'd probably ask to buy the snake at a lesser cost, and if the seller didn't budge, I'd respect it and probably move on. If I ordered a snake off the internet, I would be quite unhappy if a scar wasn't disclosed prior to paying for it.