In Spain at least, from a good ISP, and buying as a Business. Here you get two segments, mostly. Residential, which will leave you with banned SMTP and public I

In Spain at least, from a good ISP, and buying as a Business. Here you get two segments, mostly. Residential, which will leave you with banned SMTP and public IPs marked as spam everywhere. If you buy as a business, and from a trusted ISP, and tell them your use case, they will give you clean IPs. In our case, we're paying about a thousand euros a month for two optic fiber links with 100mbps up/download and two blocks of 8 public IPs, all of them completely clean.