Privately owned Public Mobile, providers of low cost wireless service in Toronto and Montreal, now has over 150,000 subscribers according to a leaked document that was forwarded to the Mobile Syrup blog.

The internal document, penned by the CEO of Public Mobile Alek Krstajic, said that September 2011 was the best month ever for the wireless companies.

Public Mobile picked up 40,000 new subscribers in the third quarter, a number Krstajic said was “50% higher than the combined prepaid growth of all 3 Incumbents (at 27k)”.

Public Mobile offers wireless phone plans without any contracts in Toronto and Montreal starting from $15 a month.

Discuss Public Mobile plans and service in Digital Home’s Canadian Alternative Wireless Providers forum .