[miguelrochefort]

> Transactions won't be free. Somebody has to do some mining.

Proof-of-Stake (as opposed to Proof-of-Work) will change that.

> Some googling indicates that a typical bitcoin transaction costs about two dollars today.

This is because Bitcoin reached the limit of transactions that can fit in a block, which causes a bottleneck, which increases fees. This has been fixed for other cryptocurrencies, and Bitcoin will soon (August 1st) fix it.