I'm not sure why I can't find relevant information for the lab testing of the product here in the sellers ' formes

The cost of lab testing the product is insane! At least two times the cost of my inventory.

In addition, it is very difficult to know exactly what tests are needed.

So is there anyone who can give me information for this matter.

My main questions are:

How can I reduce the cost of testing ?

And how do I know exactly what tests are required on my product? Because it's different from one company to another. I spoke to several companies and each received a different offer.

I hope there is someone here who can share relevant information with me.