Add ability to set a "sold" price/value

I am requesting the ability to set a "sold" price for items within my collection. When viewing the collection summary, sold value/total should be shown as a separate column and not calculated into the overall value of my collection, since I no longer own the item. This feature would greatly assist in managing my current collection and separating those cards that I have sold and no longer own, but still want to have a history of the item and its metadata.