Waterfox has a native sidebar/vertical tab feature along with container tabs that might fill your tab group needs (I stopped using chrome before they added tab groups so I watched a 4m video on them and seems like you could get all the features and more out of the sidebar).
Those truck stops that have the X gas price for cash Y gas price for credit (x < y) are a good example of a merchant passing the savings onto consumers. More niche is all the coin shops I’ve been to pass the fee onto you if you use a card.