If you like under the desk headphone holders that hold on to the desk with adhesive, the GVDV Under Desk Headphone Holder goes for $8 (holds one headphone) or $10 (holds two ~ the Type B in the listing). This is sold by the maker (GVDV Direct) with the order fulfilled by Amazon, so a Prime membership gets it to your door for free even if you only buy one. Together these two holders average 4.9 out of 5 based on 43 customer reviews. Note however that a number of the reviews received the item for free in exchange for a review ~ per the review disclaimers over there. You can filter the reviews if you only want to see reviews for Type-A (holds one) or Type-B (holds two).

UPDATE: there are appear to be a couple of other similar looking holders under the Vogek brand – you can find them all in the New Releases list.