Is selling discounted US stamps a scam or not?

I keep seeing offers on FB ads for discounted rolls of Forever Stamps selling for $39 a roll. The seller is a site called USPSstamps.com or something similar. Actually, I think there are a few sellers now. It’s not the USPS because that would be a .gov. The comments all seem fake and are about how wonderful the service is.

I asked at my PO and they had no idea about this. I’m wondering if it is a scam or if DeJoy is trying to undermine the PO and allowing off-brand stamps to be sold.

Anyone know anything about this?