Oh! I've witnessed this quietly every time I buy soda!

I'm a habitual enough soda drinker that I'm a six-pack-a-day diet soda drinker (don't judge me, at least it's not Red Bull). I notice that there's vendor collusion at Walmart for months at a time where the Pepsi six-packs will typically go on sale for a few months at a sub-$4 to $5 price (currently it's $4.98) while Coke packs will be $5-6 off sale.

Cycle three to four months and Coke will enter the $4 position and Pepsi goes back up to a full retail price for the next quarter.

I've always seen the 'cycle' of the two competitors constantly hitting a 'sale' price across various retailers.

Seems to be a pattern among all products I’ve ever encountered. I’m a heavy sales shopper. My local grocer (Ingles) will do a promo for Sargento cheese or Chobani yoghurt for instance, normal price of 5$ let’s say, then drop it to $2 for a week, then to $4 the next week, then back to full price. This rinses and repeats every 2 or 3 months for most sales products.

Sadly for this RedBull drinker, they never go on sale, at all, ever, anywhere.