google mail has the following sending limits
google apps account limits
The links above come down to…
1- GMAIL accounts
500 Emails per day, 500 on the receiving end, or simply, 500 recipients of 500 messages
2- Google apps accounts
500 recipients.. 100 a time when using SMTP
But, what is not stated is that a large number of bounced messages, or email messages that look like spam will also get your account disabled, i found that out on a forum on the internet,
In general, you can send email with PHP through Gmail’s servers for notification and the like, but it is best if you triple check the data before it goes to your account !
Click here to see how to send email from PHP through your Google mail “Gmail” account.