Create version with AdMob and version without AdMob

I'm finalizing my Apk and I want to enable AdMob to receive money from the ads, but I want to put a "No Ads" option where the user pays to remove the advertisement (temporarily or permanently). I'm always learning how to set up AdMob, but I can not figure out how to recreate a non-ad version of it (I've never messed with AdMob, so I do not know how to handle the activation of advertisements)