On January 1 of next year, Google Maps will institute a fee for users who exceed a limit of 'hits' per day. This will most likely affect sites such as travel discount companies.
From the article:
"We understand that the introduction of these limits may be concerning," said Thor Mitchell, product manager of the Maps API at Google.
"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."
It would be more accurate to say Google will impose a fee for heavy users of it's Maps API, if the site is accessed through the website there won't be a charge (I doubt it's even possible to query Maps 25,000 times in a day through the website).