Gem Bundles Gem bundles are probably the best to become acquainted with, since gems are the only resource on Arena you can actually purchase with real-world money, so they set the standard for how much everything on Arena actually costs
Dark times
This is easily one of the simplest enchanteds in Attack of the Vine, and that's far from a bad thing, as sometimes keeping a card super simple makes it easier to slot into multiple deck archetypes
Dragon Cost Reducers When it comes to getting your dragons onto the battlefield faster, cards like Nogi, Draco-Zealot, Dragonlord's Servant, and Dragonspeaker Shaman do a ton of work
Personally, I think the best option for new players would be to buy the Sapphire/Ruby deck from Into the Inklands as it comes with Locations and it offers the opportunity to dig a bit more into how cards can interact together
Next up we have collection binders