The Bitcoin transaction fees depend on the transaction size, so the fee is calculated per byte, and not per the amount of Bitcoins sent.
The default fee used by many bitcoin wallets is 50 satoshis (0.0000005) per byte.
However, paying 70 satoshis (0.0000007 BTC) per byte will get you the fastest and cheapest transaction on the network.
Miners prioritize transactions that are made with the highest fees, working down the list until the bitcoin block reaches its limit, which is about a size of 750,000 bytes.
Transactions made with low fees that are pending remain in the miner's Memory Pool to be included in future blocks depending on their priority or fee.
A transaction made with say 5 satoshis per byte may not reach the recipient for a very long time, if it is not rejected.
