Koss KPH7 Lightweight On-Ears for $2.94 [limit 5]

Disposable price without totally disposable sound perhaps, the very lightweight on-ear Koss KPH7K in the black color scheme are now down to $2.94 per pair, in new condition, at Amazon by Amazon actual. Limit five per customer. The only catch is that these too are part of the Amazon Add-On program, so you’d need a $25+ purchase (otherwise the shopping cart won’t let you buy them, even if you are a Prime member).

The other colors go for $4 to $7 (total of six color schemes). As a group, they average 3.9 out of 5 based on 450+ customer reviews.

UPDATE: Amazon has a created a page featuring a number of sub-$20 headphones/earphones.