Quote from: errornone on July 22, 2015, 02:11:54 AM

A fee at this moment is a very low value in USD (0,0001 BTC / 2cents).
But - lets hope and pray - when bitcoin skyrocket to prices like 1 btc = 100000$, the fees will be huge in fiat value!!

You do not need to worry about that. Default fee have been reduced before due to bitcoin price levels.

Default fee was reduced from 0.0005btc to 0.0001btc in May 2013 since Bitcoin-Qt 0.82 (Release Notes). In March 2014 , Bitcoin Core v0.9.0 (Release Notes) reduced the minimum relay fee to 0.00001 btc. Note that lowering minimum relay fee does not imply lowering default fee to 0.00001 btc.

The lowering of minimum replay fee has set the stage for a low "market rate" for transaction fees. If Bitcoin price skyrocketed, users have the option of sending transactions anything above 0.00001 btc fee. It means transaction with 0.00001 btc are also considered valid and will be relayed. It is still up to the miner to decide whether to include it in the blocks.

Quote from: Deuceisgood on July 22, 2015, 03:11:55 AM

Could it conceivably take FOREVER for a zero fee transaction to process?!?

Zero fee transaction could also confirm as quickly as fee-paying transactions. It has to do with the priority score and maturity of the inputs of the transaction. In very simple terms, less than 1 kilobyte transactions with more than 1 btc transacted can be sent with no fee (Wiki). I would not suggest any less experienced user to try sending a zero fee transaction because it induces stress and it is a troublesome process to remove the transaction from wallet if it did not confirm within reasonable time.

Quote from: errornone on July 22, 2015, 10:35:56 AM

if miners are not including his transaction in blocks, where in hell is his transaction at this moment? Where is it saved or written while it is waiting for a block?

It's in the unconfirmed transaction memory pool. You can view them here:
https://blockchain.info/unconfirmed-transactions