UK ISP Freedom2Surf is offering Wi-Fi access from BT Openzone's network at half the price currently charged by BT.
Charges of £4.50 per day compare to the £10 being charged by BT for the same service. Monthly vouchers also offer a saving of £30 compared to BT's £40.
"It is in BT's interest to allow us to use its sites," said Chris Panayis, managing director of Freedom2Surf.
"If we buy in huge bulk from BT it makes sense for BT to sell to us. We're also looking to expand the scheme over other companies' wireless access points."
Freedom2Surf's existing broadband customers can log-on to Openzone's 1,300 Wi-Fi access points using their current username and password.
New customers can purchase electronic vouchers using a credit card over the phone which are ready to use immediately.
An analyst's report last week warned that price competition could wipe $12bn off expected Wi-Fi provider profits.
"Operators will make more than $100bn in investments into advanced wireless capabilities over the next four years, but the returns may not be as high as initially expected due to the growing intensity of competitive forces," said Harvey Cohen, president of Strategy Analytics.
"It is not only a question of lower cost alternatives for high-speed wireless access, but of more intense price competition for an expanding number of operators.
"This increased competition is good news for wireless data users interested in multimedia applications."
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