How are transaction fees determined in cryptocurrencies?

@cornelius.fay 

Transaction fees in cryptocurrencies are determined based on several factors, but the most common method is through a bidding system known as fee market or fee market auction.

1. Network Congestion: When the demand for transactions on the network exceeds its capacity, congestion occurs. Miners or validators prioritize transactions with higher fees to maximize their earnings. This results in higher fees during periods of high network activity.
2. Transaction Size: The size of a transaction in bytes influences the fees. Transactions with larger sizes require more space within a block and are therefore more expensive.
3. Fee Bidding: Users typically have the option to manually set the fee they are willing to pay for their transaction. They can choose a higher fee to ensure quicker processing or a lower fee to save on costs but with potentially longer confirmation times. Wallets and software may also estimate fees based on current market conditions.
4. Block Space and Block Size: Each block in a blockchain has a limited amount of space available to include transactions. Miners prioritize transactions with higher fees to fill this limited block space. Cryptocurrencies like Bitcoin set a fixed block size limit, which means only a certain number of transactions can be included in each block, causing competition a**** users for limited space.

The fee market operates on supply and demand dynamics, where users compete to have their transactions included in the limited block space by offering higher fees. As a result, transaction fees can vary significantly depending on network conditions and user preferences.