I was looking for a few compact SM chasses and stumbled upon this listing. Seller accepted an offer of $20 + $15 shipping each. Only 4 left on the listing but they seem to update the quantity regularly.

Supermicro CSE-505-203B Black 1U SuperChassis Bare Chassis Model 505-2 | eBay
SuperChassis 505-203B. 9.8" Mini 1U chassis support for maximum motherboard size: Mini-ITX 6.75" x 6.75". Manufacturer: Supermicro. Supermicro Model Part Number: 505-2. Form Factor. Available Color. You will receive what is pictured in the product photos.
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