An item's sale price is made up of four parts:
List price: the price shown to customers on the item page (item price plus buyer fee)
Buyer fee: the portion of the list price that represents Envato's fee to the customer (currently set to 20% of the List Price for AudioJungle)
Item price: the price paid to the author for the item license
For items in AudioJungle, list prices are determined by Envato during the review process. We take into account factors such as quality, complexity, potential demand and license type. Prices for some items are fixed according to length. If items have more than one license type, prices are set for each of the licenses (regular and extended), with extended license prices being set as a multiplier of the regular license price.
ThemeForest, CodeCanyon, GraphicRiver, 3DOcean, PhotoDune and VideoHive have author-driven pricing, where pricing is determined at the sole discretion of the author of the item. For more information on author pricing see this article.