In some countries and with some ISPs, you cannot get a fixed IP address at all, unless you register a business and prove to the ISP that you are running a business. I am guessing they will bill you accordingly then, and still have the same shoddy connectivity. I have seen shoddy connectivity with Pyür in Germany for a whole office building. Even as a business you are not immune to bad ISPs.

I guess Spain benefits from having a former national telecom. Movistar charges me a (outrageous by local standards) €30/month for a static IP on my residential fibre