Hobgoblin Bandit Lord is hovering around $4 a card now, but the more people get to play with it (and the more they realize it can help set up an alternate win condition in goblin commander decks), the more they should be able to charge for it
There are endless variants of these cards that grant multiple bonuses, draw you a card in addition to the effect, or both
Based on the latest market prices tracked on TCG Stacked, Flaaffy is worth about $0.60 USD
The ones labeled in white have 2 classifications
The second thing those tokens make me think is that it'd be a sweet excuse to play a couple of sweet cards: Cranial Plating and Nettlecyst
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying, add any cost increases, then apply any cost reductions (such as that of Grounded for Life's first ability)