Too late for you, but for others as point of reference:
This impact socket is 1/2" drive so no requirement to add a 3/4"-1/2" adapter to the bill.
Tool Warehouse - 46mm 1/2" Drive Impact Socket - $23.50
They have a minimum $50 price however I bought three & sold on the other two to members for 1/3 of the total cost plus their individual forward shipping.
ToolGopher is only a $1 more but you get to order just one with no apparent minimum
Check around the web with a search on
SK Hand Tool 34096 - lots of tool discounters sell it but the price 7 shipping charges varies dramtically.