Thanks to a helpful pharmacist who let me know about it, I used the manufacturer's copay coupon (I think this is it: https://www.paxlovid.com/paxcess-terms-and-conditions ) and the cost of the drug for me (with insurance!) went from $400 to zero.

I don't know about "potentially no effect." It sure seemed to work well for me, and I've had covid with and without it. The difference was pretty big. I'm fairly certain the more profound difference is for those who are older or otherwise at risk, of course.