All Pobox accounts include a certain number of Pobox addresses (aliases), that you can give out to receive mail to your Pobox account. There are 2 limits: one for our domains, and one for any personal domains you may add to your Pobox account.
For Pobox domains (pobox.com, onepost.net, penguinmail.com, etc.)
Pobox Basic: up to 3 addresses
Pobox Plus: up to 6 addresses
Mailstore: up to 6 addresses
For All Domains (MyPobox personal domains + Pobox)
Pobox Basic: up to 20 addresses
Pobox Plus: up to 50 addresses
Mailstore: up to 100 addresses
Personal domains can also add AllMail, which will accept messages sent to any address at that domain, for $10/year. Mailstore accounts can add AllMail for up to two domains at no charge.
No account may have more than 100 addresses, at any combination of domains, on it. Addresses on a single account are assumed to be for a single person, and can only forward to a single Mailstore Inbox.
You can add multiple accounts to your billing group, and share access to your domains with those accounts, if you need to have mail for your domain go to multiple Mailstore Inboxes, or you need more than 100 addresses.
Addresses used to cost $6/3 addresses. Effective October 18, 2012, this charge was eliminated.