I actually have the v0.8.2-beta but i'm trying to understand this bytes thing, it's quite complicated >.<
So basically the more transactions i have in my wallet, the higher their size is and the higher the dust/transaction fee is?
When you send bitcoins, the transaction includes a reference to the transaction(s) in which you received the bitcoins to be sent. This is how the Bitcoin network verifies that you actually own the bitcoins in question. In other words, if you received
BTC2, then another
BTC3, and then
BTC1, in three separate transactions, and you want to send
BTC4, your new transaction will include a reference to two of your previous transactions. The more previous transactions are needed, the more data (in bytes) is needed to encode your transaction, and you are charged a fee based on the amount of data required. In practice, this means if you received a very large number of low-value transactions, and you want to send a high-value transaction, that transaction will require a large amount of data and will require a larger than normal fee, which may come as a surprise. The situation is roughly analogous to receiving a large number of pennies, then being charged a coin-handling fee when you take your sack of pennies to the bank.
Additionally, transactions sending less than
BTC0.01 are considered "dust" and always require an additional fee, to discourage people from spamming the network with a large number of low-value transactions. You will not be able to spend any of your
BTC0.002 without a fee;
BTC0.0019 is the absolute maximum you will be able to spend (with a fee of
BTC0.0001), though depending on the amount of data required for your transaction, an even higher fee may be required, and you will be able to spend correspondingly less.
Bitcoin is
not designed for microtransactions. Bitcoin transactions are cheap, but not free under normal circumstances (and "dust" transactions are
never free). If you have heard otherwise, you have been misinformed.