Costs for provider to provider is totally different and depends on how many IP’s the company has itself.
IPv4’s have been selling in the range of $35-50 per IP.
The smallest amount you can buy is 256x$35-50+ = $8960-$12800+
Due to these costs is why you see a lot more providers offering IPv6 only options out there. Even more from newer small companies as well who can’t afford to shell out the costs needed to provide IP’s. This is also why a lot of companies now are charging $2-5+ per month for an IPv4 address. On the high end of that price scale a company would have to rent their IP’s out for around $4.16 per month to make it pay off in a year. Realistically for most providers IP’s end up taking around 3-5 years to recover the money it costs to get more.
Hopefully those numbers help show what it typically costs on the providers ends. Most bigger companies are buying /22’s or larger which adds up even more to the costs. Just part of the business.