A lot of balance and care goes into choosing the cost of a card, more than I can express here, but looking for similar effects on existing Magic cards can give you an idea of a fair costfor example, a ramp spell that puts two lands into play ought to cost 4 mana, per Explosive Vegetation
The reveal lands enter play untapped if you can reveal a card with a certain basic land type from your hand
1 Displacer Kitten This flicker kitten made waves when it was first revealed in Commander Legends: Battle For Baldur's Gate, and it still commands an impressive over $10 price tag
It might go a little higher at some point, but this card is already close to the ceiling Ill be looking for with some of my other picks
But I think each of them could have a colored box around their name or card type, and it wouldnt make the cards any less attractive
For the alternate Enchanted version, this card is all about the artwork