Some varieties of the Sport King are worth considerably more to collectors than others. I would take the gun to a reputable gun shop in your area to get a better idea of value. But conservatively, if in good or better all original condition, you probably have a $300 - $450 gun.
On a side note - I think you will seriously regret selling your grandfathers pistol as you get older. Unless you really, really, need the money I would suggest you keep it as a memento of your grandfather. I wish I had something more of mine, other than a pocket knife - which is priceless to me.
I will agree with most of the posters in that the value is probably around $300-500, and that having a family heirloom is more valuable than the money. However, if you really want to sell it, your best bet wold be at a local gun shop (they can put in on consignment, show it in their shop, and take a commission off the sale and give you the rest). I would not recommend a pawn shop, because they will rarely give you more than 25% of the value.
You might also consider a gun show if there are any in your area, but you'd probably get less money that way. You can also run an ad in the paper, but you run a risk with meeting a stranger who might rob you or worse. A High Standard is a collectible gun, and the value is very dependent on condition.
But I would be willing to bet that in the future, having your grandfather's gun would be a great memory. When I was 14, my grandfather gave me his 16 gauge double barrel shotgun. Now, at age 57, I still take it out dove hunting and it conjures up memories of hunting with my dad and grandfather.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.