There is a lot of variance in what an IP costs in practical terms. If you need to go out and get a new IP block then that pricing should roughly break even in 1 year. In that sense, it might significantly increase the time to break even and long term margins for that type of service.
For ultra cheap VPSes IPv6 only options are becoming available for just this reason.
I wonder if we could get ultra cheap VPSs on CGNAT. You might want to run something which only makes outgoing API connections. Maybe it's just a chatbot or something that doesn't need it's own IP.
I don't know of anyone offering that service (a bit too niche and low margin). An option for low volume personal use might be to just piggyback off a public NAT64 provider though. For something a bit more enterprise, AWS will do NAT64 by default on any NAT gateways you define
For ultra cheap VPSes IPv6 only options are becoming available for just this reason.