Shopbot canada is one of the largest price comparison services in Canada.
If you have less than 50k products, you will have an easy time, but you can always request help if you have over 50k on Shopbot.
The Shopbot feed specifications are pretty well layed out, and you’ll want to optimize the usual fields like title and description.
Lastly, you can send your feed to Shopbot via FTP or URL.