It is amazing how much the prices have increased on error coins over the years. Back somewhere around 1983 I bought a fairly large group of DDO#2 1972 cents from Fred Weinberg for a few cents each and sold some of them on Ebay after the internet came out for around 35 dollars each .I thought the Ebay buyers had gone crazy and look how much they are worth now.
Yes it is priceless to you .. IMO I know when I find something I enjoy it much better than one I buy. I have thousand of really good error coins I have personally found over the years from roll searching . I'm getting too old to bother with trying to sell them and this may be left up to my children and grand kids and maybe some of my 5 Great Grand Kids . I have four kids and the youngest one is 34 . I even have two authenticated and graded discovery pieces in slabs . Heck I even enjoy finding the modern error and variety coins. The reason folks on here does not recognize your retained struck thru grease cent is probably because they are too lazy to do any coin roll or bag searching IMO After years and years of roll searching you can learn a lot from it.
I went thru a 80p 50$ bag....I never wanna see that coin again,lol. Im the same,ive got so many error coins I wouldn't know where to start if I were to sell them.
It is best to keep the coins you have looked thru because it is easy to overlook a major variety coin. In order to know what to look for , first thing is to study the design details of the coins you are going to look at for a long time before looking thru them. If you don't know the coins design from end to end then it is easy to miss the errors and varietys. I'm the one that first discovered the DDR#1 P mint Minnesota state quarters and by knowing the design is how I found it. I still had a few problems getting them authenticated but it all worked out from the help of a friend. I also am the one that discovered the DDR#1 P mint Oregon State guarters . Imagine that with how many people that are in the USA Good luck and I hope you find some good ones , don't pay any attention to the negative people and keep after it. If you need to know something just PM me. Then I could give you my email address.
I still have much to learn. I would have thrown that back as damage. Fortunately though, I keep all my copper in a box!
You need to learn how to read , Did you make it thru Kindergarten ? Or is this meant to try to make me look bad . I like humor but not this kind.