According to BBC:
From 1 January 2012, Google will charge for the Google Maps API
service when more than the limit of 25,000 map "hits" are made in a day.
Websites, especially travel firms, use Google Maps to link customers to a view of the destinations they inquire about.
Google is rumoured to be charging $4 per 1,000 views in excess of the limit.
Google maintains the high limit of 25,000 free hits before charging "will only affect 0.35% of users".
Google said it was aware that developers needed time to
evaluate their usage, determine if they were affected and then take
action as appropriate.
"We understand that the introduction of these limits may be
concerning," said Thor Mitchell, product manager of the Maps API at
"However, with the continued growth in adoption of the Maps
API, we need to secure its long-term future by ensuring that even when
used by the highest-volume for-profit sites, the service remains viable.