How to get or own your own IP address?

The website we running let people register their own URL and redirect to our website to their user account. Lets it is something similar to Blogspot.com where users can have their own URL.

The problem is that in order to do this we need to have static IP address for the DNS redirection to work. We can easily get static IP addresses from most hosting companies, but if we change our hosting company it means we will have to force all our users to change their DNS setting to our new IP address. This if very problematic.

Is there a way of owning our own IP address that we can take it with us to wherever hosting company we decide to go with? Or there there other easier solutions out there?

This can be fixed using DNS. Create a single DNS "A" record that points "your-site.com" to your current IP address. Then when all of your users register their own URL, instead of having them set up "A" records, they need to set up a "CNAME" record that points to "your-site.com". If your IP changes in the future, you just have to change the "A" record for "your-site.com" and then all of the other DNS entries will automatically be updated.