Q:

What is a feasible energy requirement to forge negative mass.

Given that a hypothetical method to generate negative mass exists (which involves intricate manipulation of subatomic particles with lasers... or some other science-fiction), what would be an appropriate energy consumption necessary to generate negative mass for use in hypothetical warp-drive technology? 
I assume it would be very high to create something of substantial negative weight. 
Additionally, would energy consumption be required to contain and store negative mass?

A:

At this point negative mass matter is something that's not theoretically forbidden but we've found no theoretical or experimental evidence to suggest it exists.  Even worse, we don't have any ideas about what sort of particles it might be composed of.
What this means in a practical sense is that we have no idea how to make it.  Which means we do not know how much energy it might take to create.
In this Stack Exchange Question: Resources to justify long distance space mining missions, I postulate that knowledge of the existence of negative mass matter at another star might be sufficient motivation to make an interstellar voyage worth while.  The purpose wouldn't be to "mine" it.  Rather we'd want to get samples to bring back so we can make some at home.
This stuff would be terribly useful for making inertialess drives, wormholes, and other nifty SF technologies.

