Theoretically they could be valued at $5, just that customs will rake you over the coals to prove it. Although they don't want these boards used so, its not useful to anyone here.
The interesting part here is they ordered 3,000 units from the start. I'm guessing they made projections based off of the AD/DD products, perhaps they sell several thousand per year.
Then maybe there was some calculation based on volume discounts starting at the 1,000 component mark.
MCP6H82 $1, mrf24wg0ma $19,
PIC32MZ2048 $10. So might be in the $30-40 BOM range? Depending on what discounts they get.
https://store.digilentinc.com/openscope-mz-open-source-all-in-one-instrumentation/