I have a collection of apparoximately 2100+ comics (98% Marvel 70"s & 80's) and would like to sell them.
I sent a list to a comic book store who said my collection is worth about $10,000. This website says its
worth $40,000. I realize its not actually worth 40 as I didn't grade them and just called all mint.
So the store is offering me $4,000-$6,000. All books are in bags with backing boards.

Should I sell them on this site? I understand his reasoning for giving me 50% of what he says is the value
but is the value given on this site accurate.

Sorry for the long question

The only way to know the value of your collection is to grade the books.

I looked at the books you have in the system, you have some books that are extremely desirable for collectors. Daredevil 1 and 2 issues of the ASM 129 could potentially be worth $4000 depending on grade.

I get weekly questions from people selling their collection. My answer is always the same. You have to balance work, time and money. The more work and time you put in, the more money you will get out. The quickest approach to selling will usually get you the lowest dollar amount. If your time is cheap then sell them yourself. If your time is in short supply sell them as a lot.
Ron