You can use one IP with multiple domains/subdomains or you can use multiple IP's (or different ports) and no domains but I don't think you can easily use one IP with multiple apps like you describe (without risk of exposing the application directories). Hover.com has domains for as low as $4.99/year so it's not a huge investment. For local development, you can point non-existing domains (e.g. myapp.test) to your IP.