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
I don’t know the Immich API, but I’ve seen several REST APIs that used the usual pattern of
GET /api/v1/user/<id> - read user POST /api/v1/user/ - create user ...
but also allowed
GET /api/v1/user/<id> - read user GET /api/v1/user/?action=create - create user ...