I paid less than $30 for my earphones that were made by Anker called Soundbuds Slim. They feel pretty comfortable compared to others I've owned. Soundbuds are lightweight and stay put while I'm running. They stay charged for a long time too.
I think Anker produces good products at an affordable price point, but I didn't like their Soundbuds Sport IE20 model which hurt my ears. They also aren't even sweatproof, even though "sport" is part of the name.