Fotodiox via Amazon offers Amazon Prime members the Fotodiox Barndoor Kit with Honeycomb Grid
with free shipping
. (Non-members can spend $25 or more to qualify for free shipping; otherwise, shipping costs $6.84.) That's the lowest total price we could find for a similar item by $5. It includes a folding, four-leaf barn door kit, honeycomb grid, color gels for Alien Bees strobes, and 5.5" to 7" adjustable reflector mount.
Amazon Prime membership is $79 per year; however, Prime is free for college students for six months, and free for parents and caregivers for three months. (Note that currently there's a waitlist for Amazon Mom.)