Meritline.com offers this 3.5mm to 2.5mm Earphone Plug Adapter
for $1.85. Coupon code "MLCK600716070870NL1" drops it to 49 cents
. With free shipping
, that's $1 off and the lowest total price we could find for such an adapter, although we saw it for a few cents less week, since expired. It allows you to plug a 2.5mm earphone cord into a 3.5mm jack. Coupon ends after 1,000 uses.