Looking to sell large lot of shells

[kebrere]

Hello,  I am farily new here, I have aqquired quite a few shells as well as coral and other things. I do estate cleanouts, these were from a Marine Biologist, that traveled extensivly.  The family told me that most of these items were aqquired before 1960. I have taken pictures and would like to post them here.  I am wondering do I have to set a price, or can I accept offers??
Thank you in advance for your advice.  Kim