Im assuming you're a new player:

1. Knight and castles maze This is an event which only obtainable for beginner , you need to collect points ( maze coins) to progress , I recommend collect around 2.9k and save it until limited time path available (greedy dragon).Spend it on the greedy dragon path especially if there is a discount.

2.Maze Event This is a same event which available for everyone , all of maze event are friendly f2p , all you need is thunder eagle breed setup and thats it you able to achieve perfect collection for maze coins (225), just keep in mind that every collection require 4 hours to refresh and you need to keep maze coins until ltp availble and spend it on happy hours

3.Team Shop If you able to find a team and get decent amount of war coins you can spend it on legendary monster cells , it is also important to invest it on the right monster , you can also just keep war coin on spend it on runes which is also one of best option for later game

4.well you know where thi$ i$ going just buy them