I'd recommend VSD3S for $45. They pretty much beat everything under $40 I've heard. If it has to be under $40, maybe VSD1S (my preference), Xiaomi Pistons, LG quadbeat (not much bass but very nice clarity for the price) from stuff I've listened to personally. There's a lot of nice stuff under $40. Depends what kind of sound you like.
Edited by ZapX629 - 7/17/14 at 4:37pm