HiFiChris published a review of the Fostex TE-02WP IEMs. With the “WP” standing for water proof. At a price point under $50 make them a good workout option.
Pros: very neutral, really good soundstage, resolution clearly above the price, value, fast and arid bass response
Cons: lack of accessories (not bothering at the little price), slightly springy cable, might be too sterile and boring for some