ethereum sender fee problem

[mdikmetas]

sory my english not good

i use meta mask and mew  im only send gas price  best low price only 1Gwei

how can i send it with an expense below 1 gwie.




I have seen some TxIDs sending them with 0.4gwei as their example.

how do they do it

I do not know how to do

sample txid

https://etherscan.io/tx/0x815071b65b6184d15b3041ecf4b6be4c23d74b2ae6058c207249c08550eb4a33


how?