There are a few on Facebook marketplace. New ones are in the 7 to 8K range. These are under a grand. Would you or would you not but a used Supercharger? - Yes, I am on a budget and I just want more HP - but not a serious build - second weekend car.
Schnelly, it’s not only that you need be careful buying an aftermarket Supercharger, but it won’t fit a 4.6l 3V without a Manifold like a TVS, or a custom piece, and you’ll spend the 6-7K for parts to get it to work properly, when you could just bolt on a K.B.with a Warranty for 7K, Tuned.
You might be able to find a “kit” made for your 4.6l, used...If you want to pursue “used” to cut costs, look down that Avenue.
There are other Mfg’s, too... https://www.americanmuscle.com/edelbrock-sc-0509gt.html
Best!
-John