There are a number of options available, however NONE are fee free.

For a business with an actual shopfront / premises, you can rent a EFTPOS terminal and customers can pay on the spot.
This works if you have a number of customers paying this way, each and every day.  But it still costs YOU to have this facility.  Many businesses will add the 2% or so when paying by credit to cover the costs.

You can integrate a merchant gateway into your website, to accept CC payments, at a COST.
Again, if you are taking 100s of orders per day, absorbing the costs (and risks associated) into each transaction can be done.

The biggest issue with taking online CC payments is the fact its a CNP (card not present) transaction.  For these transactions, many institutions will pass the loss directly back to the vendor.  You expose yourself to online fraud.

For overseas transactions, yes CC or PP is realistically the only option.

For purchases within Australia, a bank transfer can be done via several clicks of the mouse.

I assume the vast majority of RTBB's customer base is Australian, not overseas, so bank transfer is a free payment.  It reduces chances of fraud to almost zero.

For me, I would much prefer to shop from RTBB with a bank transfer and pay much cheaper prices.  But then again I don't live off my credit card or feel the need to.