Give a look at this:
Category:Straight Razor Database - Shave Library
Since you can inspect the razors you should be able to identify the maker and look up the most common ones.
There is a list of razors to avoid. Brands of Straight Razors to Avoid - Shave Library
When you inspect look for cracks that cannot be fixed and look for pits of black rust (bad stuff) that are difficult
to deal with. Watch for patterns of corrosion that hint that old celluloid razor scales emited acid fumes (bad for razors).
Scales
can be replaced.
Razors too old to have a country stamped on them are a bigger risk.
A well ground razor with enough wear to show that it was used is likely a good one.
This is not ebay so I think another forum group ....
Have fun.
Edit: I have the Clover and J.A. Hellberg nice...
The all look like shavers to me. Each has just enough wear to show that it was used and enjoyed.
Check for cracks... and even spine wear....