It kind of makes you wonder where the come up with some of these prices. you can't even move the decimal point over and make this one come out!!
They doctored the picture with Photoshop (or a similar program) but part of it got inverted (like a reversed negative photograph) and the seller wasn't good enough with the program to undo their mistake. Look at the letters on the reverse picture. The reverse is rotated 180 degrees, but the letters are oriented to the viewer with no rotation, but each individual letter is reversed. Talk about messed up! By my estimate, the coin is worth about a dollar or two.
I was just making a comment on the grammar of that sentence - but, now that you mention it, that is weird. The words themselves are not backwards, but the letters are. I have little knowledge of these image programs, so I'll just scratch my head.