Mhmm Mhmm.
You have caught the bug. Had it too once, and now we are in Symbiosis.
First! No one is in early access yet, but we are expecting the Pre-alpha test phase of Prelyria to be right around the corner.
Second, with regards to the cash shop. The cash shop is a completely optional thing, and if I were you I would look at anything you purchase there as your opportunity to world build instead of get ahead.
Many of the items like "Expanded Sigils" Aren't relevant unless you have the basic sigils already, and stuff like EP which is a currency that will be used during Exposition to help world build you cannot buy unless you have access to Exposition.
Here is where we meet a crossroads. I have answered your questions, and no doubt given you more questions. Well if you want to dive in headfirst I guarantee you will like what you see, however confusing it may seem at first, but I will only help you part way with this post (certainly if you want to ask me questions via DM I am willing)
The two questions I assume you have are what are Prelyria
Prelyria will be a testing phase of the game using the Unreal 4 engine and game mechanics, low poly, low fidelity graphics that allow for quicker implementation of assets. In other words, the Devs can test more stuff faster.
link 1
link 2
And what is Exposition.
Exposition will be a "soft launch" of the game 3 months prior to the Full launch, where players that have bloodline packages or higher will be able to get in game and spend their EP building their player made lore into the actual game of Elyria.