I make these out of commercial bun pan racks I find on local sites like Craigslist. Completed it holds 40 of the Harbor Freight medium portable parts storage cases (http://www.harborfreight.com/19-bin-portable-parts-storage-case-93928.html)
Normally, they are just a bit too wide for those storage cases. I cut a section out of the middle and join the halves using a sleeve made from steel perforated square tube picked up from Lowes/Home Depot. I make the sleeve long enough (4 or 6 holes long) so I can return it to it's precut width if ever necessary. I get it to properly hold the storage cases, mark and drill the pan rack tube, then bolt it all together. Fill the bins with whatever makes you happy....screws, washers, bolts, nuts, nails, sprinkler systems parts, springs, pins, heat shrink, etc. ... and label the cases to make pulling the right one much easier.
On one side of the pan rack I cut and fit peg board. On that I bolted a wall mounted thread checker (http://www.threadtoolsupply.com/wall-mounted-thread-checker.html). It's great to have it right there where I need it.
On the other side of the pan rack I mounted a magnetic dry erase board that comes in real handy. Under that I have a folding shelf made from some wood scraps and a bracket picked up on Amazon (UltraHrdw 11035 Bracket Foldings 12x12 WHT 2/BG).
These roll great even when loaded down and can be positioned next to whatever you're working on to save a ton of time and effort.
Estimated cost:
Bun rack from Craigslist: $40
Steel Perforated Square Tube: $10 (one $20 3 foot tube is enough for a two or three of these if I remember correctly)
Sheet of Peg Board: $10 (one $20 4x8 sheet is good for 2 racks with some left over)
Magnetic Dry Erase Board: $10
Shelf Brackets: $11 (for one pair)
Scrap Wood: $0
Wall Mount Thread Checker: $53
Harbor Freight Storage Cases: $6 each with coupon (holds 40 cases total)
Hardware: $5 (12 nuts and bolts, metal screws for mounting peg board and magnetic dry erase board, 1 reciprocating saw metal blade)