$40 will get you better quality ear buds than headphones. The sony standards are alright for $20, I've heard ok things abuot the skullcandy earbuds but do not get the full headsets by them, ever.
I've never raelly dealt wtih anything under $150 in a long time so lemme do some research before a better answer. Also, what are you susing to play music so I can find otu the impedence...