I’ll bite: how about $10 per year, less than what I’d pay for a VPN service, but more than “free” which is what I pay to run a pi-hole like service for my local LAN only. If I were in charge of one of these existing VPN services I’d offer ad blocking as an upgrade.
The service is literally a VPN with an extra ad blocking service. Why would you pay less for that?
Depends on whether the VPN service also came with the same privacy assurances that the more costly competing VPN services offer.
How does a third party VPN that intercepts all of your data have any privacy assurance?
Well, an unlimited bandwidth vps should run less than $100/year, so a dozen users and you make a profit.