Only to HSN doing unstrucks for 19.99 cent and 99.99 for small dollar. Price usually goes by size and metal content. It's easy to miss an unstruck dime or cent but just plain foolishness/carelessness for a mint employee to miss a half dollar or even a small dollar. So the smaller the denomination the lower the price as the potential is there for more examples. There are even some national dealers out there selling (at least they were) the stages of a coin set for $5-10 and you got an unstruck, a missing layer coin say a zinc coin that was just a copper core and a fully struck zinc cent. Same with metal composition a silver unstruck is worth more than a copper, nickel, or copper/nickel clad.
It's a one in a million shot to get a blank from the mint. Especially now a days with the higher quality control standards. What most people get is a unstruck planchet. When the soon to be coin is cut from the sheets of metal they are blanks they go into a milling machine which turns up their edges and turns the blanks into planchets. The planchets in turn get put between the dies and struck into a coin. So to find a jagged edged blank IMO wouldn't happen often. If the machinist didn't find it, the guy dumping the bins might or quality control and certainly someone running the wrapping machines at string and sons would.
Most slugs won't have a raised rim like on a coin as most slugs are cast and not struck and those that are have a more rounded rim instead of a crisp one with the field sunken lower than the rim IMO. There was also a trick using the punchouts from an electrical box (people were even selling them on ebay) as blanks and filling centers of rolls with them.