Is it economical to buy every character

is it economical to buy every character that comes during your gameplay??

On large maps, it is quite possible that you end up being offered more characters than you get coins for winning the map. I personally bought every character as it came up, but if you wanted to be more conservative, then you can use the character without buying it, leaving the option to buy it at some later date, as long as the character hasn’t died in battle.

well then if you bought every character, then how did you get so many hero coins. did you play the same event many times?

I played the tournament games a few times and got coins there. I also had to play a few games before I had enough coins, but on average, I think you get enough coins just from playing (and completing) regular games, especially if you are premium for double coins.