Default Best compromise battery?

I'm using the stock battery right now. I have two of them and a charger that let's me charge the second battery outside my phone. I have $10 amazon credit and was thinking of getting the zero lemon but that looks like overkill. I have the otterbox commuter case and don't feel like going much bigger than that. I would like whatever case to at least offer decent protection as well. Am I just better off throwing a spare charged battery in my pocket and swapping batteries if nescessary? I do have a huge anker charger that i could use as well but it would pull my pants to my ankles if i put it in my pocket. Maybe I should find a thinner and lighter battery pack?