If you're looking for inexpensive, I'd check KZ in-ears.
A simple Ebay search to give you a price idea. You can spend $20 on up to $70 or more. I bought a $35 set earlier this year, they sound great. You may want to find some replaceable foam buds for them, I guess that depends on how they fit in the first place.
I have these Sony’s I found at BestBuy for $19 and they sound pretty even on my iPod and computer. If it’s just for scratch work while you’re out and about I wouldn’t spend more than that unless you decide to go real IEMs which start at $399.