This reminds me of the “free iTunes song” promotion Apple and Pepsi ran in ~2005. Some Pepsi bottles had codes under the bottle cap that could be redeemed for a free song; non-winning caps just said “Sorry Try Again”.
You still had to buy the soda to get the free song, but if you’re going to drink soda anyway, spending a minute or two picking a bottle with a free song gave you a nice little bonus.
The mistake Pepsi made was that you could actually make out whether a bottle had a winning or losing cap by looking into the bottle without having to open it (https://methodshop.com/2005/02/hacking-pepsis-itunes-giveawa...).
You still had to buy the soda to get the free song, but if you’re going to drink soda anyway, spending a minute or two picking a bottle with a free song gave you a nice little bonus.