Tooltip Help?

[roaaaarrrr]

Does anyone know how to display gold cost in the hover-over tooltip. This is displayed on about half of the items in my map, but not in the rest, and I can't figure out how to make it all the same.

For more clarification... when you hover over an item, the tooltip is displayed. On some, there is a small picture of a gold coin followed by the gold cost. I would like this to be the case for all items, but cannot figure out how to do this. Any help would be appreciated.

 

[Tom Jones]

Check your items gold cost, Stats - Can be sold by vendor and Stats - Can be sold to vendor.