I have, in another hobby. I think you have to be somewhat known. They contacted me, they sent the stuff I made a few videos reviewing the products.
I was fair and honest in my assessment, something a company doesnt like. If you dont lie about it, sing their praise and generally suck them off in front of everyone, they complain and will never use you again.
Basically you have to whore yourself out to them, you have to have an audience otherwise who the fuck are you and why would they give you anything.