[Django]-Best method to store list of foreign keys in a model?

A classic many-to-many relationship would work until you have a quantity of a certain meat in a parcel and you want to calculate the total price.

The many-to-many relationship can only give you the set of the types of meats in a parcel.

You would need another model to store the quantity information. In Django, this is done with the "through" model in the many-to-many relationship https://docs.djangoproject.com/en/dev/ref/models/fields/#django.db.models.ManyToManyField.through

class Parcel(models.Model):
    customer_address = models.CharField()
    date_wanted = models.DateField()
    meats = models.ManyToManyField(Meat, through=MeatInParcel)
class Meat(models.Model):
    name = models.CharField()
    cost = models.DecimalField(4, 2)
class MeatInParcel(models.Model):
    parcel = models.ForeignKey(Parcel, on_delete=models.CASCADE)
    meat = models.ForeignKey(Meat, on_delete=models.CASCADE)
    quantity = models.IntegerField()

see https://docs.djangoproject.com/en/dev/topics/db/models/#intermediary-manytomany for more details on how to use add(), create(), or set() to create relationships