I recently picked up a big (40"H 37"W 32"D) 25-drawer flat file cabinet that was in New Hampshire, and after figuring in gas for driving, what I paid for it, and money spent on refurbishing it with paint, polish, cleaner, and new lube; I’ve got about $400 into it:
I also just checked Ebay to see what’s listed, and there are several good deals on some big metal flat file drawers. The big 25 drawer type retail new for $3,000 to $5,500, so they are really good deals at under $400:
A couple smaller ones:
And if you ever wanted to set up your own Woodin Lab, then there’s this seller who has 64 5-drawer units on pallets for $500 total (6,000 lbs of drawers):
It is an absurd quantity, but is an amazing deal. You also see these drawers listed on Craigslist quite often since so many places have ditched this type of storage in favor of going digital, or else there have been many places that have fallen on hard times and have closed down, leaving these drawers behind.