The transaction fee in cryptocurrency is the cost you have to pay when making a transaction on the blockchain. There are two main types of fees: network fees and exchange fees. Network fees are paid to miners (Proof of Work) or validators (Proof of Stake) to process and confirm transactions. Exchange fees are the costs charged by exchanges like Binance or Coinbase. The fee amount varies depending on the type of currency, network congestion, and the platform used. Some blockchains like Ethereum have high fees when the network is congested, while networks like Solana or Polygon have lower fees. Understanding fees helps you optimize costs when investing.