I didn't realize until now that both The Beer Store (yuck) and LCBO (hooray), including Vintages (

) list all their product prices on-line, including items on sale in the case of the LCBO. I think that wine prices in Ontario tend to be a bit lower than the Canadian average, thanks to LCBOs huge buying power.
The best wine-buying location in Canada has got to be Ottawa-Gatineau. You can spend ages browsing in the Vintages on Rideau at King Edward and then drive five minutes to the SAQ across the bridge to buy bulk table wine. (At least that used to be the case, is that SAQ still there, Acajack? I've been away for a few years)