The best affordable in-ear headphones for use in the home music studio are Sony's MDR-EX58V.
Let me first state the obvious. These headphones are not considered an industry standard for in-ear monitoring. There are certainly more professional in-ear headphones out there. Our question however is about the best affordable in-ear headphones.
I have used the MRD-EX58V's in my home music studio for quite some time now. Though they are designed for use in portable music devices they still are a great affordable alternative for home studio applications.
What I like about these ear buds is that they are right around $30.00 a pair. They can handle full band audio including bass and drums, without breaking up. They have a built-in volume control and they sound great for the price.
The MDR-EX58V's work perfect for individual recording stations in the home music studio. Though I am not recommending them as a good mixing set of headphones, they are a great affordable option for in-ear monitors and the recording musician.
For all of these reasons I consider Sony's MDR-EX58V's to be the best affordable in-ear headphones for use in the home music studio. I've included an affiliate link below to a great online price for these headphones. Please note that if you do purchase these headphones from the following link a small portion of your order will go back in Home Music Studio 1.
SONY MDR-EX58V/BLK In-Ear EX Earbud with Volume Control - Black