Price: $49.99
Don’t pay over: $39.99
Description: The darling of the portable headphone world.
Good at: Staying on your head, when your in the gym.
Don’t be fooled: They are the king of classic headphones.
Rivals: Audio Technica ATH-RE3, Sennheiser PX100/200, Skullcandy Lowrider
ebay: Starting at $30.00. rarely see used examples on ebay.
Replacement parts: Koss Porta Pro replacement ear pads
Accessories: Koss [...]

Price: $19.99
Don’t pay over: $9.99
Description: very popular inexpensive ear plugs
Good at: being a good pocket money earbuds
Don’t be fooled: into thinking that these would be better than the standard ipod earphones.
Rivals: JVC Marshmellow, Sony MDR-Ex32Lp, Skullcandy Buds Ink’d Earbuds
ebay: ebay, amazon, its all the same.
Replacement parts: Replacement cushions
Accessories: Koss volume control, Koss headphone carrying case, [...]

Price: $29.99
Don’t pay over: $19.99
Description: Basically, a neckband version of the Porta Pro. should do for joggers, but so would most neckband headphones, like the mighty iGrado’s. Apparently they’re dark blue.
Good at: staying on your head when running
Don’t be fooled: by the word ’sporta’. The Porta Pro can also go jogging with you.
Rivals: Sennheiser PMX60, [...]

Price: $19.99
Don’t pay over: $15
Description: Koss Porta Pro without the headband
Good at: being modded it would seem.
Don’t be fooled: by the whole clip on thing. Pay a little extra and get a headband.
Rivals: Philips SHS4701, Sony MDR-Q22LP

ebay: Starting from $13.99. They do start from $8.95 but shipping is $13.99
Replacement parts: Replacement cushions
Accessories: Koss volume control, [...]