I was able to register for a single-user free account this morning by doing this.
How to Get the Free Edition of Google Apps (One Mailbox)
Alternatively, hereâ€™s a quick and simple workaround that will still let you sign-up for the free edition of Google Apps even though Google has officially retired the free edition â€“ all you need is a free Gmail or Google account.
Go to appengine.google.com, sign-in with your Google Account, a standard account email@example.com NOT a domain GMail account and create a new Application. You may fill in any dummy date and click the â€œCreate Applicationâ€ button.
Open the â€œDashboardâ€ and on the next screen, click the link that says â€œApplication Settings.â€
Scroll down a little (refer to the video tutorial) and choose â€œAdd Domainâ€ to associate a domain with your App Engine application.
Thatâ€™s it. Now you should see a special link* to sign-up for the free edition of Google Apps. You may either use your existing domain or buy one through Google Apps.
[*] You have to access this link through App Engine as Google Apps checks the HTTP Referrer information before serving up the sign-up page for the free edition of Google Apps.