You can use sir Euphy's Multi Shop . Its right here >>>> http://pastebin.com/raw.php?i=YftccqDs
just look for this line:
setarray .Currency[1],513,513,513,513,513,513,513,513;
and change the 513 into the Skull's item id which would be 7420 . Thus it will look like this
setarray .Currency[1],7420,7420,7420,7420,7420,7420,7420,7420;
Then look for this :
setarray .Shop1[0],1202,5,1229,20;
*change the 1202(itemid) into your desired item to be vended, as sir Euphy stated,
// Currency: The ID of each shop currency, // in the same order as the shops. // Shop order follows that of the select() call, // and is formatted "ID1,Count1,ID2,Count2,..."
Cheers!