There are two main types of price change models: Exponential and Linear.
Exponential Model
Following the exponential bonding curve, the price of an NFT will increase by a certain percentage (also known as delta) each time an item is purchased from the pool. Conversely, the price of an NFT will decrease correspondingly each time an item is sold to the pool.
To calculate the corresponding decrease amount, convert the percentage into a decimal exponent (for example, for 50%, the exponent will be 1.5), and then divide the price by this number.
For example, a liquidity provider can create an NFT<>ETH pool with a starting price of 2 ETH and a delta of 50%. Assuming they provide enough liquidity, the price of the NFT will increase to 2 (1 + 50%) = 3 ETH after purchasing the first item from the pool. After purchasing the second item, the price will increase to 3 (1 + 50%) = 4.5 ETH, and so on. At any time, if the NFT is sold to the pool, the price will be divided by 1.5.
Linear Model
Following the linear bonding curve, the price of an NFT will increase by a fixed amount (known as delta) each time an item is purchased from the pool. Conversely, the price of an NFT will decrease by the same amount each time an item is sold to the pool.
For example, a liquidity provider can create an NFT<>ETH pool with a starting price of 1 ETH and an increment of 0.1 ETH. Assuming they provide enough liquidity, the price of the NFT will increase to 1.1 ETH after purchasing the first item from the pool. After purchasing the second item, the price will increase to 1.2 ETH, and so on. At any time, if an NFT is sold to the pool, the price will decrease by 0.1 ETH.