These are $60 from J&R so a bit above your budget but if you are willing to splurge these are BY FAR the best workout earphones I have ever used!
Jaybrid Endorphin Rush
Got these on a whim knowing little about them except for their claims as being specialty exercise headphones and their LIFETIME warranty for sweat.
Sound is absolutely amazing with especially good lows and great isolation. Construction is extremely solid and near-bullet proof with an excellent design made to run inside the back of your shirt.
I cannot speak highly enough of these as exercise phones!
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