Welcome to the LE Forums!
LE is B2P, you can either use EHG’s Store and buy one of the supporter packs or buy it on steam, that steam purchase would automatically include the lowest Supporter Pack (Ardent Gladiator)
Also as a sidenote, you can use either the steam client or the standalone client. Regardless where you purchase.
Stash System is very clsoe to PoE’s, but way better IMO and it is compeltely seperate from MTX (all in-game gold). Here you can have a loot, they introduced that new system 2 patches ago.
Yes, EHG will call them “Cycles”, but there is no detaield information yet.
LE will have a MTX Store, but we don’t have much informations on that. We don’t have exact informations for Loot Boxes, so we have to wait for more informations on their MTX System.
Also not informations about that yet. We will probably get futher informations together with general MTX Informations at some point hopefully.