Question about buying the expansions

[MilkieTea]

The Starter Edition is to remove the free trial restrictions and is little more than your first subscription fee, even providing 30 days of game time.

Endwalker gives you access to all previous expansions as well, but it requires you to already have at least the Starter Edition.

The Complete Edition gives you both the Starter Edition + Endwalker.

So it would make the most sense to get the Endwalker Collector's Edition unless the Complete Edition is cheaper because of a deal. I don't know if the Complete Edition is able to be registered when you already have the Starter Edition.

Once you have bought Endwalker, you can upgrade the previous expansions to their Collectors Editions to get their mounts and minions through the mog station.

I can confirm the complete edition is able to be redeemed if you purchase the started edition. I bought the starter edition and then the complete edition because on sale it mapped out a tiny bit cheaper than to buy starter+ShB.