First. EBay sellers are not allowed to charge you more than they have advertised. If the seller says the price is $5 and the shipping to Canada is $1, he cannot charge you more than $6, no matter how many items you buy.
There is no fee for buying on eBay.
There are many sellers on eBay. Are you sure that you are buying from only one seller?
Are you buying from the USA and is the seller * using the Global Shipping Program?
If he is, he cannot combine or discount shipping.
He can re-invoice you through Paypal, giving the numbers of the items you purchased on eBay in the text description. Then he can, if he wishes, combine and discount shipping cost.
You may have to pay Canadian duty and sales tax as well as a Canada Post service charge if the total cost, before shipping is more than $18 US (or $20 CDN).
*If the items are actually less than $5 each, he is stupid to use the GSP. Actually that would be true if the items were under $50 each.