Bitcoin transactions fee is the charge taken by different miner to complete an transaction. In current time its transactions fee is higher than before and this is because of its increase users number and less block size. Block size of bitcoin mainly influence the transaction fee. Small block creat transaction traffic and this thing ultimately increases the transaction fee. Block size varies according to the miner set up. I think in future bitcoin will be increase its block size due t heavy transaction load in its network and this thing help  to reduce bitcoin transactions fee.