Let me preface that I am very fond of my eyes. I know people who have lost their eyesight in accidents or suffered eye injuries from not wearing safety glasses. I know some people will scoff at paying above $5 for a pair of safety glasses, but then again that is a very narrowminded view when you consider the importance of eyesight...it's irreplacable, priceless, and you can't operate equipment blind.
UVEX safety glasses (I used to use the Genesis models). They are excellent cheapies, generally made in the USA (except the mirrored ones) and available in clear, smoke, and IIRC, green for torch use...if you can't afford a higher price safety glasses, or need backup pairs or semi disposable pairs...choose UVEX.
Personally I now use a pair of Revision "Sawfly" glasses. Very high ballistic rating, good coverage, high optical quality, very scratch resistance. I use them every day, 8 hours a day. Just under $100 for a pair w/ clear and smoke interchangable lenses. I've got a pic from another board where a pair of these glasses stopped a very large piece of shrapnel from killing/maiming an officer in Iraq. The lenses themselves are replacable for $20 apiece if you loose one or damage it beyond repair and there is a clip in prescription carrier that can be filled at your eye doc if you need eyeglasses.
And that's just for general safety glasses use. For special applications, such as using a grinder or weedeater, I have a very nice Uvex Bionic faceshield. I also have a pair of UVEX clear goggles for times when I need something sealed against dust.