No $$$ for Leech, and I can't spend NX on gach since I need to begin stacking AP resets for HP Washing once i hit 135. I have 10934 hp and have a okay-ish stonetooth sword. I've never done Bigfoot but I've heard that is a good place.
Just doing skill quests gives a decent amount of exp as well. When i did my paladin quests (i know, not a hero, but still), I was 123 before i actually went out grinding again.