Quote from: AceBitcoin on September 06, 2015, 01:32:43 PM

Greetings fellow bitcoiners. I am no Pro in the world of Bitcoin for sure.But I have learned enough to open a new wallet with Blockchain.info and am about to fund it with about 0.5 BTC through bank deposit.I am still unsure about the mechanics of bitcoin payments.I am also confused about what others have told me ,that the full amount in the wallet will be used, like say I have 0.5 BTC in my wallet and the vendor charges 19.8mBTC for their product,will the entire sum of my wallet be used or is there a possibility that I can get the remainder balance/change into my wallet after deducting the vendor/miner fees?And btw can mBTC be deducted from Bitcoin? Terribly sorry for my ignorance.

Yes you'll get your change back of course. What the person was talking about was change addresses. You don't need to worry about that, change addresses are a feature that makes your Bitcoin payments harder to track, they often confuse people who try and track their coins and they see the coins are being sent to strange addresses.

How it works is if you were to send 19.8mBTC to someone and you had 0.5BTC in your Bitcoin address, your client will actually spend all of the 0.5BTC and send back the remaining 0.49~ BTC change to you at a new Bitcoin address, which makes it harder to track but also confuses lots of new users as they expect it to go back to the same address they sent from.

The unit doesn't matter either, though you might have to convert to BTC from mBTC if thats what your wallet is denominated in.