Ocean Protocol offers 3 types of pricing options for asset monetization. The asset publisher can choose one of the available options which best suits their needs while publishing an asset. Once the pricing type is set, and the asset is published, the pricing model is permanently fixed for the asset and cannot be changed later.
In a fixed pricing model, an asset's value is fixed as long as it is available in the market for buying. Publisher can set the price by deciding the value of a datatoken in terms of the number of Ocean tokens. The buyer needs to pay the exact number of Ocean tokens to get 1 datatoken. The publisher has an option to update the price of the dataset later anytime.
A [FixedRateExchange](https://github.com/oceanprotocol/contracts/blob/v4main/contracts/pools/fixedRate/FixedRateExchange.sol) smart contract stores the information about the price of the assets published using this model.
Publishers can choose this fixed pricing model when they do not want Automated Market Maker(AMM) pools to decide the price discovery. If the publisher has already analyzed and estimated the worth of the dataset and is ready to sell an asset at a constant price, this is the suitable pricing model.
The publisher creates an Automated Market Maker(AMM) pool of Datatoken and Ocean tokens in dynamic pricing. *AMM* enables unstoppable, decentralized trading of assets in the liquidity pool.
A *liquidity pool* is a reserve of tokens locked in the smart contract for market making. A buyer or a seller of an asset exchanges token **x** for token **y** or vice versa. AMM calculates the exchange ratio between the tokens based on the mathematical formula above.
Ocean Protocol facilitates the creation of Datatoken/OCEAN liquidity pool with [Balancer smart contracts](https://github.com/oceanprotocol/contracts/tree/v4main/contracts/pools/balancer).
While publishing an asset with dynamic pricing, the publisher decides the initial ratio of Datatokens and Ocean tokens in the pool, thus setting the initial price of an asset. The price of an asset is later dependent on the pool's liquidity and the price impact of trade in the pool.
Publishers can set the pricing model of an asset to Dynamic pricing if they want the market to decide the asset price and thus enable auto price discovery.
The below image shows how to set the Dynamic pricing of an asset in the Ocean's Marketplace. Here, the asset price is initially set to 50 Ocean tokens.
With this pricing model, datatokens are allocated to the [dispenser](https://github.com/oceanprotocol/contracts/blob/v4main/contracts/pools/dispenser/Dispenser.sol) smart contract which dispenses data tokens to users for free whenever they are accessing an asset.
Free pricing is suitable for individuals and orginisations working in public domain and want their datasets to be freely avialable. Publishers can also choose this model if they are listing assets with licenses that requires them to make it freely avialble.
