* Transactions are always free. However, users have the option of paying a very tiny processing donation (like $0.001 for example) to receive "priority processing" of their transaction. In the future, this should result in faster processing of their transaction. (In fact, the system is designed so that transactions that pay $0.002 fee will have even higher priority than transactions that pay a $0.001 optional processing donation.) However, at this point, with the current transactional volume of the network, paying this optional donation will have no effect whatsoever - because every transaction is already processing as fast as technically possible. Note that, even in the future, all transactions that do Not pay the optional "priority processing donation" will still be processed. For more technical details about this, see bitcoin.org
** Past performance is not necessarily an indicator of future success. This site gives no financial advice. Nothing on this site should be construed as giving financial advice.
*** Additional tools required to make transactions completely anonymous. See "How to make Bitcoin transactions anonymous".
Ŧ Bitcoin protocol is designed to not need any encryption of the transmission. This is because the data is already encrypted to begin with. All the data is visible to anyone, however no one will be able to read anything anyway. While most banks use RSA keys to authenticate peers (usually 1024-bit or 2048-bit RSA keys), Bitcoin uses EC (elliptic curve) keys of size 160-bit, which most experts consider more secure.
Of course, as for your Bitcoin Wallet being stolen by a person or a computer virus, or accidentally deleted, it can only be as secure as where you store it, and who you entrust it with.... just as with any other form of money, cash, gold, silver, etc.
See our safety tips under the Security tab above.