I ordered these presumably no-name earphones for 6.99 on amazon:
Link: http://www.amazon.com/gp/product/B0064BII6C/ref=oh_o01_s00_i00_
Received them today and to my surprise they came with a Sennheiser product
manual and it also says Sennheiser PMX80 on them. However, they are not in
the original Sennheiser packaging but a generic clear plastic package. Not
sure if that means that it's an open box item, but even then it would be an
awesome price (original price of these earphones is $59.95, amazon has them
for $32.49 right now).
Pretty decent reviews (also note that the product picture here is identical
to the "no-name" earphones):
Link: http://www.amazon.com/Sennheiser-PMX80-Sport-Behind-Earphones/d