Well you are sort of correct with saying that $20 extra for RGs and $40 for PCB but remember that the 360 hack is a fairly difficult one so you can’t just disregard the labor involved. TRNG is said to have sold one for $75 + shipping before. It would probably be a little less than $75 since he’s also building a whole stick, but still more than $40.
$300 plus shipping is enough to do the whole thing but not of TRNG quality.
For the DOA4 stick, you could probably get someone to do the whole project for you for a set price. Say $250 or whatever, and have them worry about getting the stick and modding it. This would be a lot easier than you buying one then sending it to them (also save a bit on shipping). Or commission someone, buy a DOA stick online and just have it ship directly to the person doing the job.
I would honestly like to try out a 360 hack but I don’t want to shell out $40 for a pad and not even be able to test it out in-game (not owning a 360 and all). I would only be able to do electrical tests.
Anyway, my 2 cents. Change would be appreciated : )