eBay (US/UK): The online auction house sees cards of all rarities and values listed, from single cards priced in the pennies to rare finds fetching hundreds and thousands
Promotional cards are typically given away at special events or as a promotion
Well, just stop the other person from combo-ing off or locking you out on the first turn, and then play a Monastery Mentor and so many cheap or free cards that you kill in one or two hits, while also having a resilient, wide array of threats, to ensure removal cant stop you
But what makes these expansions stand out
Salubrious Snail (who puts out some great video content on YouTube) has a site with some handy calculators you can use, for free
Additionally, this tier encompasses decks with limited data, making it challenging to accurately assess their placement in higher tiers