Energy cards are how you pay the cost of attacks
The power of each card is determined by the strength and willpower scores printed on them, and if you defeat your rival on a quest along the way, you get to move closer to 20 by the number of lore that card holds
To Link Summon a Link Monster, you send face-up monsters from your field to the Graveyard, then Link Summon the monster to an Extra Monster Zone that is unoccupied (or if you send a monster from your Extra Monster Zone to the Graveyard you can also place it in that Extra Monster Zone)
Beyond initial investment, factor in ink, maintenance, electricity, and labor costs over a 3-year period
Many customers printing proxies, Commander cards, cubes, or custom tokens specifically want the finished cards to feel as close as possible to standard MTG products once sleeved and played