Vintage Advice

I just recently began shaving with a straight razor and now find myself seemingly being pulled in deeper each day. Since my wife enjoys estate sales and antique/consignment stores I think I will now have a reason to accompany her besides just being her chauffeur.
That being said, what should I be looking for on any vintage razors I may come across, and what should I stay away from? Besides the obvious of rust and pitting, are there any other red flags on a vintage razor to look out for. Also, is there some sort of reference as to what certain straights are worth or is it just what someone is willing to pay for one? Any & all advice is welcome!

Thanks in advance,
Ron