Airbag question for you...

Hey all,

I'm new here and I need to pick your brains on something. I've got a 98' Mustang, and I got my poor baby in a little fender bender and the airbags went off I'm fixing her back up now and I need to put in some new airbags, but I have a few questions about it I'm hoping you can help me with. First, I can't afford dealership prices, they're just out of their minds. So I was hoping I could pick some up online or at a salvage yard...but, I have no idea of how to know if its a good deal, what's a good site to buy from, if they're safe to use, and I have absolutely no clue on how to install them. Do any of you guys know how to install them? Or any tips of what to look out for when not buying it straight from a dealer? Any good sites you know of to get them. I appreciate your help, and thanks in advance!