I've just recently gotten into the hobby of coin collecting, And I think I found an "Error coin", And I was wondering what it's average value would be. The error is in the mint-mark, For some reason my camera refuses to take extremely zoomed in shots, But from looking at the coin under a magnifying glass, It appears to be the "D" mint-mark, But for some reason the D is not hollow except for a tiny hole in the middle, It sort of looks like a doughnut. I'm not sure if it was double-struck or if it was struck again by a P mint-mark, I'm waiting to buy a better quality magnifying glass to check this.
There does not appear to be any errors on the reverse side of the coin, But I also posted a photo of it in case I might have missed something.
Hopefully these photos will be good enough to verify is this is an error coin or not. You can click the photos to expand them and get a better view of the mint-mark.
Also, Thanks everyone, I have received a lot of help in the short time I have been here.
It is normal, that was caused by a worn mint mark punch. For another example of this, look at a 79-S proof- it will be a blob as well(unless you happen to have the much rarer Type 2 clear mint mark that utilized a new punch towards the end of the year for proof coins)