I have been trying to understand exactly how the gas pricing works in the Ethereum Wallet. I wanted to estimate the gas consumption for the transfer of 1 ETH from one account to the other, so I simulated this transfer with the testnet.
In the first time I did it, the estimated fee consumption was 0.00042 ETH for the tranfer of 1 ETH from one account to the other. I tried to do it again to see if anything changes, and I realized the fee varies around this value, sometimes above it, like 0.00045 and sometimes below it, like 0.00038. I've executed the tranfer of 1 ETH again but this time with 0.00038 ETH and it worked perfectly.
So, if the gas price is limited to 10 Szabo for now, why does this variaton occur, even if it is a small one? And also, if 0.00042 ETH is only an estimated fee and the real fee may be below it (which would explain why the transaction with 0.00038 ETH worked), then why the remaining gas that was not used didn't return?
Thank you very much