Deadly commander and militant combo!(explainations included) 

Militant and commander is good, but you can literally 1 tower molten with just military base on some maps like u turn or any maps that are long and have a few bends, and military base is more relevant in all stages of the game so i'd go for that for any new player-

i used this strat to get to 50k coins lol had 5k left so i grinded molten with it