I don't like writing on my storage boxes, unless I put it there, and then it's pencil. However, the 25 empty boxes new, you'd probably spend close to if not more than $100 right there. I want to say the 3200's sell for $4 and the 5Ks sell for around $5 each. Now consider the boxes are used and written on, but if that doesn't matter, it's probably worth it if you can use the boxes.
Going through the boxes, especially if the seller is spot on with the description, could be tedious. However, there is a sliver of a chance there are some gems hiding within as well.