Open to suggestions.

A little background... I started playing MTG in 1997, big fan for a good long time, quit playing in 2006. I haven't touched the game since. I have a 500lb tote full of old cards I haven't looked at in almost 20 years now. No one wanted to play, and I moved to far away from game shops to bother continuing anymore.

Fast forwards to today, as a joke, I got Worlds Smallest Magic: The Gathering Exclusive Collector Set Featuring Ajani VS. Nicol Bolas and Heroes VS. Monsters Duel Decks and Exclusive Playing Dice (off amazon) and it was a big, all be it tiny, hit with everyone. I now have 3 people who want to play the game with me. I have no idea where to really start. 2 of them have never played the game before that. 1 of them has some of the newer booster boxes laying around, but hasn't actually played it much. Myself, I have 0 clue where to start anymore. None of us have interest in playing outside of our group, so this is just casual.

I want everyone to be on an even playing field, so, so far I bought 2 starter deck kits. The Lord of The Rings: Tales of Middle Earth Starter Kit and the Bloomburrow Starter Kit. I had little luck finding a full list of pre built decks you can order outside these starter kits. (I remember there being a ton of these pre made decks you could buy way back when).

No one is allowed to add or remove cards from these decks.

Should I consider getting more decks after those 2 kits? Am I better off just buying more premade kits? Are there any Kits that are better to get than others? I mainly just got the LotR and bloomburrow ones because I liked how they looked. I have no actual clue as to what is inside either kit. I am just wondering if it is possible to find single decks I can buy, is it just in kits? I really enjoyed the Ajani and the Nicol Bolas decks I tried, but cannot seem to find their full sized versions (outside the $130 kit I found on Amazon). What I do keep running into is something called commander decks, and plainswalker decks. I want to keep things simple with 60 card pre made decks though. I'd also like to keep things cost effective, in case everyone decides to quit this new hobby.

Can you even play older kit decks against newer ones? Will newer ones have unfair advantages? Would it be cheaper to find some older deck lists and buy singles?