Not a lot of good VPNs out there would let you stay connected to there VPN for a long time. It's up to you if you want to purchase one or not.
Another way to change your IP permanently would be by unplugging your Router for 5-15 minutes, then check to see if that changed it.
If that does not change it then you would need to contact your ISP.
You can change your IP permanently by doing this:
Unplugging your Router for 5-15 minutes, then check to see if that changed it.
If that does not change it then you would need to contact your ISP.
You can also change your IP by getting onto a VPN. Note that your IP will only be changed while your on that VPN.