Best Buy offers the Marvel Earbuds in Iron Man (pictured), Hulk, or Thor for $2.99 with free shipping. That's tied with our April mention and is the lowest total price we could find for any style of Avengers earbuds by $4. They feature 20Hz to 20kHz frequency response, and 13mm drivers.

Of note, these earbuds are also available in Avengers for the same price, but only with in-store pickup.

Update: Note that both the Iron Man and Hulk earbuds are available for in-store pickup only.