Selfhosted

I'm late to the party, but could everyone answer me this- how often does you're public IP actually change with any of your ISPs??

With the numerous companies I've used, the ONLY time I've ever seen my IP change is getting a new modem through, say, Comcast or whoever. It goes by MAC address, and if you use Comcast and then set to bridge mode and use your own device, that's a new MAC so you'd get a new public IP. Swap ISPs obviously a new IP.

I've NEVER randomly received a new IP when using the same equipment consistently, so I'm not sure why everyone's so worried about dynamic DNS stuff.. Maybe outside the US is different? I've lived in a few States and it's always the same. If you make a hardware change, just note you should also double check your IP and update it, that's all.

i have a little program for dynamic dns running in docker that checks every few seconds for an IP change and swaps my DNS records if it gets rerolled.

works well on my home network, I can use my domain for all my private services local and remote through wireguard :)

If you only need it to be accessible inside your home, then you just need to run your own DNS. Have your dhcp point at your DNS and your DNS declare itself the master for your domain.

To get full functionality, you'll probably want to have your registrar point to the public IP you get from your ISP as the domain's authoritative name server.You should be able to script it to update the registrar when your ISP changes your IP, but that usually happens infrequently enough to do manually. Obviously can't do that if you're behind CGNAT.

To get Lets Encrypt certificates, you can do the DNS challenge. If your ISP gives you a (even inconsistent) public IP, you can do fancy 'views' with your selfhosted DNS, where it responds with private IPs inside your network and your ISP-given IP outside your network. I have certbot set up to expose my DNS & web server just before it starts its renewal process, then close the firewall after. Once you have the certificate, you can move it to where ever it will actually be used.

but a friend told me that to get one I either need a VPS with a public ip (which just takes all the fun out of selfhosting) or purchase a static ip

Neither of those are requirements. Just buy a domain at a registrar that allows you to dynamically update an IP address with a domain you have there. Look into DDNS update scripts and/or your own internet router, many routers have that feature built-in already.

Yes it's possible. You can buy a domain name and then do literally nothing else if you want.

If it's just for LAN use, you don't even need to buy a domain name. You can use anything under the home.arpa, test, or internal TLDs. https://en.wikipedia.org/wiki/Special-use_domain_name