I am pretty sure that this is post mint. Just can't figure how it was done so clean without any cut marks. It is almost perfectly straight also.
It depends. Your clip isn't very large, and its circulated, so its probably not worth more than $10. For everything you need to know, and quite a bit more, see my recent thread on Incomplete Planchet Errors.
Although some may say it's worth something, try selling it for that. If you took that to a coin store, coin shop, coin show, you'ld see very little to no interest in such small errors. You could probably buy a similar one in those places for $1, but to sell yours, not likely. Sorry.
Trends for a straight clip 10% or less is $5, but I agree, try selling it for that. Someone building a set may pay a dollar or two for a rim clip...
Carl is right on the price - if it is a clip. I think you would be lucky to get 50¢ for it. I tried to sell some on eBay significantly more clipped that yours and managed to get $1.25 for a double clip. However, I am not so sure it is a clip. If a clip, the inside of the rim should be circular. This one does to look to be to me.
Mind telling me why ? It seems to have the characteristics of a genuine clip. The edge of the rims slope down into the clip and there is weakness, granted slight but still there, on the opposite side of the coin.
I don't see a clip for sure and it's so minor - it could easily have been I don't see a clip for sure and it's so minor - it could easily have been ground off by something and smoothed over. Straight clips generally are not so weak on the opposite side as this. I have my doubts on this one and it's so minor to not really be worth anything.