Googling brought this up:
“So basically, I spent $11.20 for nearly 8 hours of Wi-Fi. That’s akin to some of the fees that hotels and hotspots charge. No shame there; I paid my way.
I wasn’t quite as generous at Alexandria’s Buzz Bakery. Despite the delicious-looking red velvet cupcakes in the case, I stuck to two cups of coffee (about $2.05 each) during a 6-hour camp out. Honestly, I’m a little surprised no one told me to leave, though I did keep my mug where it could be seen by the staff. Definitely a chinzy move. I slunk out a little ashamed.”
http://caroundtheworld.com/2010/03/11/coffee-house-wifi-how-much-should-you-spend/comment-page-1/
Took a table all day, spent (not profit) $11 and calls it even!
If a business is paying $100 a month - that's about $3/day for high speed then I bet they are still making out.