centimental value

A strong attachment to a family heirloom due to one's either being able to make a significant income from da ownership/use of said precious object, or knowing dat it will fetch a "pretty penny" if put up for sale.

If someone claims to have a special emotional attachment to an item at an estate sale --- especially if said object is of considerable value --- it's entirely possible dat he really means dat it is "of centimental value"; i.e., dat it would be worth a lot of money to the right buyer, and so he is merely wanting to selfishly turn a tidy profit by selling it.