money

How important is it to invest money into LOL? Because I am thinking about doing so

Tbh its not really that important. Of course its much more satisfying playing a champion with a cool skin but you really dont need to invest alot of money at all. It takes along time to grind up and get skins, new rune pages and more without investing any money tho.

Depends if you want cute skins or not. Skins aren't needed and champions can be bought by playing the game enough to earn BE but if you wanted champions quickly then I guess buying them would be fine though expensive.

You don't need to invest a single dollar.

I am a f2p player and have fun easily. Also, riot really rewards loyalty in comparisson to bying your way.
So just keep playing