Quality Cellz via eBay offers the refurbished Sony In-Ear Headphones 2-Pack in Black, model no. MDREX10LP/BLK, for $9.99 with free shipping. That's $4 under the lowest total price we could find for two pairs of refurbished headphones elsewhere. They feature 9mm drivers, a 3.5mm connector, and hybrid silicone earbuds in S, M, and L.
No warranty information is provided.