Generic topical flea products... Are they safe?

[Dogdragoness]

Hi guys I was recently at the flea market & saw sargents gold flea drops for a dollar (i know I know lol) & couldn't resist thr deal & picked up a couple of boxes. But I got home & stumbled across an article written by this lady whose dog almost died from a reaction to this product.

But I know they can also get reactions from thr 'good' stuff too, my question is is it safe for me to use? I have used many OTC flea meds over the yrs (I just can't afford frontline or advantix ) without a prob. So would it be safe for me to use it on my dogs?