You should be aware that there are likely to be all kinds of special pricing deals when you sign up for Wi-Fi access. Mostly, this is all to the good.
For example, most establishments that provide fee-based Wi-Fi access also have some special, introductory offers. In this spirit, it is typical to find a coupon at Starbucks good for a one-day pass on T-Mobile Hotspot.
However, you should also know that some Wi-Fi networks allow individual hotspot operators who are part of their network to charge more than the standard network price for access. For example, the business model of the SurfHere network is one in which it is more important to support hotspot providers than it is to create a national network for individuals. So SurfHere is quite clear that many of its hotspot providers can (and do) charge more than the standard network fees. If the location charges more than the standard network fee, your credit card will be billed for the overage.