coral rocks shells pricing

[caes]

Hi guys,
This might be an odd question, but my dad has a big box of coral/rocks/shells he has stored in the garage for ages

i was wondering if you guys can give me a rough estimate of how much this stuff costs so that I can sell it as we will never have a big enough house to have a large aquarium anymore. He says all this stuff is real. No artificial stuff except for the plastic and decorations.

any help would be appreciated thanks guys!