Telepathy has a million foil printings which makes me think for 7th foils to be expensive, the number of printings doesnt matter if the card is good and 7th is the best version
As these examples show, the complexity of paying an alternative cost can range from very simple (pretty much like casting the creature normally from your hand, like when evoking, warping, or overloading), to requiring a bit of work (like flashback requiring the spell to be in your graveyard), to demanding very precise timing (such as madness)
Adventurers Inn Look, its Radiant Fountain with a subtype
Compare to Tragic Slip, and you will know what I mean
However, this rule may change depending on the type of Pokmon and trainers you intend to choose
Thats because this three-mana blue enchantment lets you draw cards whenever an opponent casts a spell as long as they dont pay one mana to counter the effect