I started playing this game almost 4 months ago, and the truth is I am really enjoying it. I play another grind mobile game (SWGOH) and there, after almost 3 years I am a top player. There I am strictly F2P. If you can get to top positions in your board, you can earn enough game currency to stay there, and although you will not get all shiny toons on release, you will get them second time they appear.
After the first week playing here, I learn that F2P can never ever compete in this game with P2P players. Is easy knowing the best heroes are only on portals (season, atlantis, event) and you need game currency to get them, and you can get very little game currency to do that summons.
So, after a month playing and seeing that I liked the game a lot, planned to movel to C2P. If you plan it and attach to the budget, it will really boost you and for a subcription price (Or little more tharn a movie ticket with popcorns and coke).
With about 20€ monthly, you can get the 5x1,09€ event offers, for 1000 gems and the 4x2,29€ atlantis offers for 1600 gems plus 100 atlantis coins. Even the monthly VIP pass will get you 900 gems a month for 5,49.
Only with this you are able to do a 1x10 pulls montly, plus other 5-7 pulls with epic hero tokens and atlantis coins you get. If you go up another 10€ when there are special offers (only buying the 2,29€ for 200gems and the ascension mat) you can do 2x10 monthly pulls, and here is where it comes interesting.
As F2P i got Wu Kong and Triton with some epic and atlantis coins, but the progression was really slow, so
following this C2P approach, in november I did a 1x10 pull in teltoc event, and, although I didn’t get any teltoc hero, i got Richard, my first 5* along other useful 4*, in november a 1x10 atlantis pull gave me Mok-Arr, another 5* and other 4* heroes and now in Avalaon knight event I got Evelyn 5* HOTM and lancelot from the event. Also got Santa Claus 5* with an epic hero token I had saved for season summons. Later I will do the monthly atlantis 1x10 summon and will see if the odds are with me 
Now I am starting to have nice heroes, doing good titan damage, helping my guild and can even start to win in platinum arena. Is actually a lot of fun for 25€ monhly on average, but the fun fact is… this money doesn’t come from my well earned salary, it comes from online surveys where I can get about 30-50$ (yes dollars, good survey pages are not european, but paypal solves that 
) monthly (25-40€) without much effort.
So know is the perfect simbiosis. I have a montly budget, the money to spend on it and the planning 6 months ahead done, and fullfil it is just… awsome.
If you like the game, but see no progression as F2P and don’t want to spend… I recommend you to follow this path. With time you will eventually have great heroes (many will say that u can do the same as F2P getting them from TC20, and that is partly true, but you can’t get the featured heroes there) and can level them up in a linear progression (I actually have 4 5* and i could almost level to 4 tier them, but Mok-Arr will wait a long time a guess xD)
Just my 2 cents… Have fun and merry christmas 
I only got zimkitha