Found the Rubbermaid Fasttrack Bench Blox Storage Kit [homedepot.com]
and Small Metal Shelf [homedepot.com]
on a clearance end cap marked down to $5.82 compared to around $20 normally. Great deal if you are already invested in the Fasttrack system.
Note, I checked Brickseek for my area and it had no saleable quantity anywhere near me yet there were still some left at my Home Depot, though I'm probably going back to get the rest today.