What's the cheapest way to buy a large number of Magic: the Gathering cards on Cardmarket?
There is no definitive answer to this. I've come across this problem myself and thought about it for quite a while to try to come up with a heuristic and/or reasoning.
In the end it depends how much time you want to spend. I believe I ended up using the 150 most expensive cards (or rather the cards above the ~0.10€ to 0.20€ threshold because below that everything is irrelevant) and sent those to the Shopping Wizard. Then I went through those five sellers and checked every one for the other missing cards (saved in a second Wants list of course). Here you have to cross-check etc but sorting by price and name worked for me.