Possible Duplicate:
Is there a fee for cancelling a building?
How much does it cost to cancel a building/unit/add-on? By this I mean, if a barracks costs 150 minerals and I started building one, what amount of minerals is returned if I cancel the building?
This question also applies to add-ons and units.
I saw that salvaging a bunker returned 100 minerals. Is this true? It doesn't make a lot of sense to me. Shouldn't cancelling a building probably return all funds spent?