With orders of $25 or more, Amazon offers Prime members the Marvel Iron Patriot 3 ARC FX Hero Mask, model no. A2124, for $3.44 with free shipping. (Non-members can spend $35 or more to qualify for free shipping.) That's $8 off list and the lowest total price we could find. It glows in the dark and features adjustable straps.
Note that this item is part of Amazon's "Add-on program;" it can only be purchased with an order of $25 or more.