This. Also getting some bands would be a cheap investment that might have saved you some space/money. If the reason you bought the lat pull-down attachment was because you can't get enough reps in for pull-ups, use band assistance. You can also use bands for face-pulls and a variety of other stuff, as well as providing accommodating assistance/resistance to your big lifts. Not necessary, but extremely useful for their cost.
A low box is also fairly useful if we're taking cost and space into account. Not a must-have, but nice.