Salvage Titan

• WWizards of the Coast2020-08-07
  Official Ruling
  To determine the total cost of a spell, start with the mana cost or alternative cost you're paying (such as Salvage Titan's alternative cost), add any cost increases, then apply any cost reductions. The mana value of the spell remains unchanged, no matter what the total cost to cast it was.
• WWizards of the Coast2020-08-07
  Official Ruling
  Casting Salvage Titan by paying its alternative cost doesn't change when you can cast it. You can cast it only at the normal time you could cast a creature spell.
• WWizards of the Coast2020-08-07
  Official Ruling
  You may activate its second ability only if Salvage Titan is in your graveyard. To pay this ability's cost, you may exile any three artifact cards from your graveyard—including Salvage Titan itself. If you exile it to pay the cost, however, it won't be returned to your hand when the ability resolves.

Rulings via Scryfall