A lot of people recommend Deathknight Armor, but I honestly don’t rate it in terms of value anymore and think it needs an update.
The two main bonuses it gives over F2P armors are (1) bonus XP, and (2) bonus Gold/Souls, depending on whether or not you would otherwise have Dragon or Celestial Armor equipped.
(1) is largely irrelevant in the scheme of things, although I guess it might be cool to have a really high level at some point.
With regards to (2):
The amount of Souls you get from a regular battle when not using a Soul-farming team is negligible, and a bonus +50% to this probably isn’t going to make a huge difference at any point
If you are using a Soul-farming team, the modes in which it’s best to do so aren’t usually also the same places in which it’s best to earn Gold (high-level Explores, PvP).
- Delves are also a great place to earn Gold (and Souls!), but I don’t believe the Delve-specific Room rewards (or Chest rewards) are affected by Armor, and so wouldn’t be relevant. If someone can confirm this,
Therefore, you can get away with using Celestial Armor when you’re specifically farming for Souls without affecting Gold tooo much, and use Dragon Armor the rest of the time when the difference in regular, incidental Souls will be negligible.
The main benefit of Deathknight Armor is therefore (imo) a Quality of Life one, in not having the navigate menus to switch between Armors, which can admittedly be cumbersome.
Tl;dr: Deathknight Armor is (imo) overvalued and needs an update.
Imo, the best things for a new player (/any) to spend money on would be:
A missing Event Weapon Flash Offer ($5 USD) for a Doomed Weapon that converts a colour to Doomskulls, e.g. Doomed Crossbow/Glaive
the $2 USD flash offers for Gems and Vault Keys
(Unfortunately) the Campaign Elite Pass in Week 10 of the Campaign if you have been able to complete all of the Tasks, as $10 USD for a Mythic (or similar) and other bits and pieces is pretty good value (just unfortunate because of the way it temporarily excludes F2P players)
Maybe the Sunday Dungeon Offer ($5 USD?), I haven’t really done the math on that one, though