For a successful free transfer or exchange, you need Energy and Network Bandwidth points. Points of Network Bandwidth are awarded free of charge every 24 hours in the amount of 5000. This is enough for 15-20 transactions per day. There is no free Energy on the Tron network. You can get energy by freezing your Trx through your e-wallet. Important: when frozen, Trx will be unavailable for transactions for 72 hours. If you do not want to freeze Trx, then the energy commission will be deducted from your balance in the form of Trx. You can always find out the cost of Energy and Bandwidth on the official website: https://tronstation.io/calculator.