mtg cards like three visits Nature's Lore and | Proxy Then shuffle your library TIL it's financially cheaper to

They created silly moments and allowed players to get creative and make their own jokes, but the more impactful, mechanically relevant stickers were the ability and power/toughness stickers, which allowed you to permanently alter a creature

Since they get to deal damage, it even works as an interactive spell

In fact, many pieces of fast mana were controversially banned in Commander recently

Not quite as strong, of course, but still very impactful

Manufacturer's Suggested Retail Price (MSRP) does a lot to regulate the costs, so retailers have less flexibility to set prices on booster boxes based on relative value and scarcity