So here's what I've been able to learn over the past year. Part of what you can do to cut costs as a cosplayer is buy damaged pieces. Sometimes these can be helmets, pads, swords that are brand new but came out of the mold bad.
My helmet is a good example of this.
Here it is, as I got it. Well, almost. It came with a visor but I had already started working before I thought to take pictures.
See the big ugly dent in the top? Yeah that's bad news for a lot of people. Good news is, you can fix it.
First, clean and prep the area, then do this with it.
And no, that ISN'T bondo. It's actually drywall plaster. Many layers of it. Many, many layers of it. Why plaster and not bondo? Well, for where I live at there's high humidity. Bondo doesn't like that environment and refuses to dry normally. It'll hold for a while, a very long while, but then you'll start to see it flake. It also is smelly and heavy. And can be pricey too. So I've layered up, and it looks bad. Time to sand. A small area like this I like to do it by hand. Personal preference and that's pretty much it.
After sanding, it looks like this>
Nice and smooth. But wait, I'm missing detail lines! Oh noes, whatever shall I do?
I put them in and I cut deep since I had some sanding left to do. This also helps keep the lines clean as you won't have as many cracks in the top layer.
But then, after looking, I decided it wasn't level and filled the lines back in for a redo. This was the end result:
A little bit more sanding (I can never leave well enough alone) and I went to paint.
This is with the lights and after I added a little dirt.
So that's a completed helmet for under $100.