The conversation you're having with your daughter is one two adults can have. It's a deep, meaningful conversation that encompasses life itself. It shows you're intelligent and wise.
Discounts often work against the customer. Discounts often involve spending more than saving money. For example, let's say six beers are $15. An alcoholic wouldn't want to miss out on a discount on ten beers for $20. Someone who normally drinks six beers will end up drinking all ten that day. Discounts are often attempts to increase consumption.
I think she is intelligent and getting wiser - I am just a bumbling guide :)
Your example reminds me of the Finns who go to Estonia and Latvia for cheap beer and alcohol -they end up drinking it more often.