Good Fly sheets with neck protection?

I live in VT and my mare just gets eaten alive by flys in the summer. She is out in a herd of 6 and they attack her so bad and her neck looks like brail everyone else has no bites on them. I want to get her a nice fly sheet because bug spray does not work that well. I do not want to buy one that cost over $100 because I do not want to spend that on something that might get ruined with one roll. However I do want it to stay on. It must have a neck cover because that is where they bite her the most. I am just looking to see what people have that works well. I also have to figure a way to make the neck peice to stay up with out a halter because they do not wear them when they are out. She also does not like being left inside, she is parshly blind and likes to be next to another horse at all times