The pinpoint sight costs $7.99 USD according to the Nerf website in the "Related Links" below.
I have the Nerf magstrike and it cost me $30
Read the instructions from a RECON cs-6 it has a picture.
the nerf vulcan costs about 49.99
19.99
$31.54
about $40
29.99
20-50$$$$$$$$$
$2.00
there is a Nerf red dot sight available at target, but they are EXTREMELY hard to find and its unknown if it was discontinued, frankly the quality control is rather poor, much like other attachments, making it not necessarily worth the effort.
around $40 U.S.
around$10.