You can purchase an ecobee4 at:
HomeDepot.com and retailers
BestBuy.com and retailers
Lowes.com and retailers
Is ecobee4 available for purchase in Canada?
At this time Amazon Alexa Voice Service is not available in Canada. To ensure the best possible customer experience, the ecobee4 will only be sold in the US. If Alexa Voice Service becomes available in Canada, ecobee4 will as well. For now, Canadian customers can choose between the ecobee3 lite and ecobee3 smart thermostats – both featuring category leading smart technology including room sensors.