It costs you a card but not really
The most expensive cards are typically very rare, often released as limited-run promos or tournament prizes
$40 for five foil basics or $30 for five non-foil basics definitely creates squiggly feelings about value, which means that the only value these cards can be given are those who like the art
If you activate the mana ability of Shaun & Rebecca, Agents while in the process of casting a spell, activating an ability, or during a window to activate mana abilities when you're asked to pay a cost during the resolution of a spell or ability, you won't mill cards right away
I play Pokmon TCG Pocket every day, and I have since it launched
Proto-Cyber Dragon X LIGHT Level 3 [ Machine / Effect ] ATK 1100 DEF 600 This card's name becomes "Cyber Dragon" while on the field