Are we referring to the Newegg 'recovery disk' options at $9.99 (i.e., no license key included)? I did not see any suspiciously low pricing there, otherwise)
Anyone can download the ISO onto am 8 GB flash drive from MS... for free. Been that way a long time. They are basically just preloading the ISO onto media for you, only the uninformed would think it is a valid OEM/retail installation source...I would think, anyway)
The OEM Win10 Pro pricing seems about right, however, and as it is not a retail box, I'd not be surprised at 'scratch off' key....; so naturally, once someone sees/has the key, they are not risking returns, as nothing would prevent dishonest buyers from returning it, and using the key anyway, to the detriment of any...