There are paramedics and doctors here, and then there are people who read Preparedness forums on the Internet all day and stayed at a Holiday Inn last night. Not quite the same...

It's worth perhaps two sets of recommendations, one assuming no practice and no info other than what's printed on the package. For a total medical n00b like myself the $30 product might make more sense if it might work and does no harm, even if a paramedic might find the $10 product more functional.

One issue not raised so far is storage temperature. If this is a car FAK that stays in the car when you go to work then temperature matters a lot. I'd need not less than 20F - 160F tolerance and many medicines aren't rated for that. Even adhesives in bandages might have problems.

PS. On the two occasions I was first to the scene both were urban auto accidents were the victim seemed unlikely to get worse before EMS arrived, so I followed the "do no harm" rule and only monitored until responders appeared. One lady had her face rearranged by the steering wheel - at least her unused seat-belt was probably undamaged - but any wrapping or bandaging I might have done seemed likely to just make the paramedic spend 20 seconds cutting it away.