Would installing a supercharger in my Tacoma kill my Fuel Economy?

A supercharger pumps more air into the engine. This means more gas is required. If more gas is not supplied then lean burn happens and the engine will melt down (piston tops). So it is a given that forced inductions (of which supercharges are one method) will hurt fuel economy. It doesn't matter if you drive conservatively or not with a supercharger because it is pumping more air into the engine at all times.

You don't have fuel economy in a Tacoma, so don't worry about it

Throwing a supercharger on an engine not set up for it will kill more than just your fuel economy.

Depends on how you drive. Forced induction systems can actually improve fuel economy at low rpm cruising, but if you stick your foot in it, then you will pass everything but the gas station.

For the most part, yes. It would really depend on the amount of boost you want to add. Because the more boost, the more fuel you need to compensate (usually means a higher volume fuel pump and injectors, plus a richer PCM tune).

But still, no one installs a supercharger and then drives as mellow as they usually do. You'll find your foot in the gas more. So, yes, it will kill your fuel economy.