This week WestJet increased its fees for Basic economy fares for flights to / from Transatlantic destinations, such as Dublin, London, or Barcelona.
Expect the $30 fee to double or more, from $60-$71 for your first checked bag and $90-$107 for a second checked bags, payable on new tickets from the 12 February 2020 or for any travel on or after 31 March 2020.
Rates are subject to tax and payable in either CAD or USD, depending on your route.
Here's an updated page of WestJet's fees for such journeys > LINK HERE
In my mind, another reason to avoid Basic fares altogether as a checked bag is still, at the time of writing, included in higher categories of seating.