I don't think it would be noticeable if you just made the mask with straps (clear or not). Just make sure to put it on before you pull the hood over your head. If you wanted to do strapless then as SailorEarth said use spirit gum to stick it on and don't paint the areas you are going to be using the spirit gum on.
As far as making it goes, simple leather masks are apparently relatively easy to make and very nice quality (but you'd have to buy a leather cutting tool in addition to the leather itself so the cost probably wouldn't be worth it if you are looking for something cheap):
If you want to buy a leather mask there are a ton of people who make and sell them, but they tend to be a bit pricey (you could probably find a simple black one for cheaper).
And pretty much anything can be made out of craft foam if you want to go that route.