Well, technically you can’t change the IP address assigned to you by your ISP. Any other IP address you set up manually on your device (out of the network address of your ISP) will make it unroutable. In other words, your internet connection will stop working.
You can’t achieve that without a VPN. A VPN creates a virtual network interface on your device, which in turn gets a virtual IP address. As a result, the network traffic from your device gets routed/tunnelled across the VPN provider infrastructure.
I might be skimming above but hopefully, you get the idea of how that works.
I agree with @Mirdarthos. This question is ambiguous. The thread might be closed as this is a general discussion topic rather than a support question.
On second thought, you may use:
- a browser with built-in obfuscation capabilities, which is similar to having a vpn client installed. (E.g. brave with its
tortabs) The only drawback of this approach is that some websites will often require that you prove them you’re a human through captcha or something like that. - an open proxy server, but they generally disappear as fast as a
in 
so you might have to update your proxy every couple of days or even hours.