You can order directly from ebay.com as well. I have ordered Senn CX 500 twice from there, around $40 or so including shipping, per piece.
For that budget your best choices would be:
Sennheiser CX 500
Little bass, but tight and not thumping at all, but good sound clarity.
Soundmagic PL50 or PL30 I think.
Ultimate Ears MetroFI
And some other similar competing models from Klipsch etc.