How do I get a Droplet's dedicated IP address?

Droplets do not have dedicated IP addresses, only leased ones.

When creating a new Droplet, we lease it a static IP address from an available pool. This address remains associated with the Droplet until a user chooses to destroy their Droplet, in which case the address returns to the available pool.

However, in addition to the Droplet’s static IP, you can have one Reserved IP address and up to 16 IPv6 addresses, depending on which datacenter the Droplet resides in.

Configure your firewall to allow outgoing traffic through ports 80 and 443.
Use this guide to gather information about your firewalls and diagnose problems.
Snapshots do not retain the IP address of the Droplet they were created from, but you can use reserved IPs to assign the same address to new or redeployed Droplets.