Decking Prices. Once you determine what kind of decking materials you'll need to build the structure, it's time to get down to price. While the average cost to build a deck averages between $4,000 and $10,000, that doesn't account for the materials.Here is the average cost of each decking material, broken down by average price range per board: It's important to know what board sizes you'll need to purchase for your deck.ecking Prices. Once you determine what kind of decking materials you'll need to build the structure, it's time to get down to price. While the average cost to build a deck averages between $4,000 and $10,000, that doesn't account for the materials.