Its service starts with 50 SMS credits for each user,each sent SMS is counted as one credit SMS.As per its criteria,every reply received adds on 5 credits subject to the maximum of 50 SMSes at a given time.
Incidentally,although Google has not made any official statement on it,its free SMS service came live on chat windows of many users on Thursday evening,according to a report.
The same report said:”Google is rolling out the service in partnership with cellular operators.”
”You can always send an SMS to your own phone, and then reply to that message multiple times. Every time you send a reply message, your SMS credit is increased by five. Effectively, you’re buying more messages by paying your phone company for these outgoing messages,” said the report quoting Google as writing on its chat help portal.