It's actually the easiest part for me so far! It's the blasted jacket that's driving me nuts.
Yep, I'll be making them for $5 for our cosplay group at Ani-Magic. Aside from that, it depends - but it'll probably be a little more since $5 covers materials pretty well, but not the bandaids for my bleeding hands.=) Probably just $8 or something, though.
Anyway, this is more or less how mine will be constructed. I've only created a "draft" so far to test construction methods, but it seems to work well. The "real" collars will be far more accurate.
the base - craft foam
the metal - thin aluminium sheeting
I cut out two pieces of craft foam, with wire in between them to hold a circular shape.
The sheet aluminum was cut out, and mounted on another piece of craft foam (to provide the depth for the "screen"). The screen was just cut out with an x-acto knife. The screen on my draft was a piece of lighting gel, although I may find some thin plastic for the other collars. For accuracy, I may run some rubber tubing around the metal, but otherwise, it looks fine with just the craft foam. I'm also going to use some leather on the back for comfort.
They slip on and off and don't blink(I may experiment with that later; but right now...eh.).
Here's a picture of the "draft" collar:
(ignore the glue gun mess that I didn't clean up)
Besides the tendency to cut one's fingers on sheet metal - it's really quite easy!