(presuming you mean $CAD for Canadian dollars, not cdn)
$4cad = $2.90usd = 13.2c/slice
$5.50cad = $4usd = 18.2c/slice
That’s 44.5c each.
That’s 125% profit. Given that a common margin aimed for is 100%, this is a good deal with your over priced products. And I don’t believe you can’t get basic white bread for less than $4cad in Canada.