So, I'm not really selling IP space, I'm selling a service, so bare with me.
I need to get a /24 IPv4 to allocate to a customer, which means I need to take a /32 IPv6.
Seeing as the price of a /22 IPv4 is the same price as a /32 IPv6, why not take the space and help a few people out?
I'm proposing that I rent out some /25s of IPv4 space, along with a /48 IPv6 and transit via a VPN. I'd be multi-homing and there would be a pair of VPN tunnels to keep things reliable. It's an easy way to get a publicly routable block of IPs, for not much money, for home labs etc.
If this sounds interesting, drop me a line. I'm thinking $40 for a /25, per month.