There as so many good ideas for making a ballast here on TBN that something must work.
I like the 3/4" pipe through a 40 or 55 gal. drum. Fill it with whatever - sand, concrete, even water. Easy on, easy off. But some welding required where the pipe goes through (reinforcement) and something for the top link.
Just use what you have available. Here are some others:
I've seen some great ideas for home-made ballast boxes on here, but since I have zero welding experience or equipment, and pretty much nothing solid, compact, and weighty (i.e., 800 lbs) that can be hung with chains off the back, a factory ballast box seems to be the best idea at this point
Again, a lot of my FEL work is or will be in tight spaces, so compactness is highly desirable - hence the ballast box and not just any convenient implement