Creating the ultimate hypothetical SNS/Ring of fire firearm

I wasn't sure where else would be best to put this, but I personally love Saturday Night Specials and cheaper firearms in general, like my Cobra FS-380 and even some of the 9mm and .45s Cobra made among other guns. I've always pondered how I would go about designing one of these guns or how people purchase production tooling and designs from defunct companies and restart production with minor changes. Also how people manage to modify their existing guns using parts from others (like using a slide from one ring of fire gun on another). So in this hypothetical situation let's act as if we are the board/owners of our own company here.
Some things to keep in mind,
1. Cost per firearm retail shouldn't exceed roughly $150 (or known historical examples from recent history)
2. You can also make suggestions such as; "use the slide from X, extractor from Y, and..." so on and so forth.
3. Have fun and keep it civil, in the end this is more of a fun thought experiment!

Some starting questions to help spur thought:
-What material would you use?
-What caliber?
-Revolver? Semi Auto?
-Target size?

Have fun all and can't wait to see what people think of!