Orlando wrote:HotS is the easiest one, try that. If after getting to know it you feel like you want more, you can try LOL or Dota 2. Just remember that Dota 2 is full f2p and nothing (gameplay wise) is behind a paywall. Now LOL on the other hand...
Not sure where you get that LoL is pay to win? you cant even buy the ingame currency needed to get the items that do give you an advantage, that is purely made with in game earnings. you can purchase boosts for both XP and their ingame currency, but you can not buy anything with money that gives you any game play advantage whatsoever over anyone else, only your time playing the game does that.
to the original point i believe League of Legends is easier to learn than DoTa 2, both communities are full of toxic people, pretty much any competitive scene that you rely on other players for a victory will pull out people that think their crap dont stink.
as for playing on your own, thats fairly ok, it does make the game harder as you will lack communication or even a little synergy with the person/people you play with, as with most games that you can play with friends, its always more fun doing so.