Nintendo in my experience:
Physical: Get it right on release day (or in the first week after) in retail for about 40€, otherwise you will have to rely on rare good retail discounts to get it below 55€
Digital: Don’t you even dare to think about discounts
Imagine getting a 404 or 500 error. Then archiving that on archive.org (and screenshot that dialog on steam) and accept the terms. If there’s any problem and they say you violated the EULA, point them to the terms you accepted.