transaction fee advice

[xIIImaL]

i just pay some satoshis like 4000-5000 satoshis for a transaction of 0.025btc acctully my mycelium wallet caluculate the fees it self when i choose the amount to send and when i set the lowest priority

When you sending bitcoin with the low priority means it will take more time complete the transaction and some hours and more also.
As halving and mining blocks reduced as per halving policy.