It changes with the tech, and availability. I find a good way to find new stuff is to go on to Amazon and search for what you're looking for. The first part is to sort everything by price: low to high. Next, and this is the key, on the left side, sort that list by 4 or more stars. This will eliminate all of the products that consistently fail, as well as everything too new on the marked to have any ratings at all. Be very careful with the results though, only look at products that have ~100 reviews. Too often you will get 1 single, 5-star review that doesn't accurately reflect product reliability.
Just looking at the results I under this criteria I can see a number of earbuds for under $20 which should all perform ok unless you're looking for high-end audio. If you're looking for actual over-the-ear headphones then those seem to start around $50.
ps. NEVER buy anything from Amazon with more than 20% combined 1 and 2 star ratings. This literally means that 2 our of 10 products, or 20%, will fail almost right away. WAY too high of a failure rate to even bother with that product. That's when you know you really are getting what you pay for, and what you paid wasn't enough.
