Most of the stocks in an IPO are purchased by investment firms or large corporations - so it’s extremely uncommon to have no willing buyers.

The IPO price usually also allows for a pretty decent discount on the projected valuation. So, those big investors are looking to get in early and get as cheap as they can. So for something like this, there will be buyers.

That said, entertaining the hypothetical where no one buys: the IPO is likely canceled, in the most hilarious embarrassment in a good while on the market. If just a fraction of the expected shares were sold, they may be subject to a mandatory refund. Then the company can regroup and try again later, or just take the embarrassment and go.

My ISP charges a good chunk for static IP (because they consider it a business connection). However, my $10/mo VPS (which I already had for other projects) has its own static IP and I can easily proxy individual requests through it as needed. Have looked at VPS instances for $5/months before.

Depending on the service, your ISP, and how easily you can change IPs in the registration, as others have mentioned, you could just give them your public. I’ll say my own public does change at least twice a month, so if I can’t automate updating a registration, it goes through VPS or it’s a service I just skip.