dumbstruck wrote:
Why is it so hard to get the most logically needed valve in the world...
an extra inline 3/8 x 3/8 shutoff valve to put between your expired
copper one and the standard flexible hoses going to sink faucet?

Probably because not too many people would consider putting 2 shutoffs in
series.

I certainly wouldn't consider it the "most logically needed valve in the
world".

Nothing can be found locally, so i want to order online. The closest
thing i can find is plastic and im not sure is compatible with male and
female metal standard mating

I'm curious what stores you've tried. 'Twere it me, I'd try a contractor's
plumbing supply house. If they didn't stock one, they would know where to
order it from - if they exist - so there wouldn't be any guesswork as to
whether they were compatible or not.

Many kitchen and bath "design centers" have plumbing counters in the back,
just like many lighting stores have electrical supply counters. That's
where many of the contractors do their business.