Esso's terminals supply E-10 gas out of Toronto, Oakville, Winnipeg, Regina and Saskatoon. All terminal locations also have regular gasoline.
http://www.imperialoil.ca/Canada-English/files/Products_Industrial_Wholesale/IW_rack_prices.pdf
Shell supplies E-10 gas out of Toronto, Oakville, Winnipeg, Regina and Saskatoon. Saskatoon only has E-10 regular.
http://www.shell.ca/home/page/ca-en/pricing/rack_pricing/app_rack_pricing.html
Petro-Canada supplies E-10 out of Montreal, Toronto, Oakville, Regina and Saskatoon. They also supply mid-grade E-5 out of Montreal, Regina and Saskatoon as well as mid-grade E-10 out of Montreal. Saskatoon and Oakville do not have regular or mid-grade without ethanol.
http://www.online.petro-canada.ca/eng/prodserv/fuels/rack/rck-prc-rslts.aspx?Prod=1&Freq=1
There is a 1 cent price premium for E-10 over regular gasoline at the wholesale level.
As regular fuel, E-10 required by law in Manitoba and Saskatchewan. Co-op, Husky, Mohawk and Sunoco use ethanol blended regular exclusively, and Sunoco actually owns an ethanol plant in Sarnia.
E-10 has a 3-4% penalty in energy content, but the thing is it is also being used in place of MTBE as an oxygenate since MTBE was found to pollute ground water. It was the next best thing. Doesn't hurt that governments see it as an environmental and economic aid policy tool either.
If your car runs like [censored] on it, check your fuel filter. On an older carbed vehicle, you might be running it a touch lean, too.
I need to find out if Parkland Industries or Chevron's facilities produce E-10 gas. Co-op's refinery in Regina obviously would due to producing for the Saskatchewan market.
As well, the pricing above reflects unbranded terminal rack. This means that all of this gas is basically the same until it gets put in underground tanks and treated with the brand's additives. I am not positive on this but I have heard the treat rate is something like 1 US gallon in 8000.