Why do you want to have the diagnosis before seeing a physician? (I'm legitimately interested in the answer.)
In my experience, it's about 50-50 with helping versus hurting making the correct diagnosis and providing accurate treatment.
Even in the US where you actually have to pay for medical stuff, it can't be more than $10 or so for a quick consultation?
You also have no idea of the cost of various diagnostic actions they might take. I once had blood drawn and got charged $600 for it because the lab they chose was out of network. I didn't even know there was a cost, let alone which labs to request.
Or you could see it this way :
$150 to have a nurse put a popsicle stick on your tongue and tell you that you are very lucky to have presented today because you have a suspicious growth - which on examination turns out to be a rare form of cancer that is easily cured if detected early, but most certainly fatal otherwise
It's times like this I realize just how different the rest of the world is.