It's the expense of getting the extra components, such as the regulator, and even the enamelled wire, that put even the original poster off building it. That's why I supply kits for everything I produce.
Alkaline batteries are very expensive and not needed for 30mA circuits.
Out of more than 100,00 kits, no-one has commented on the fact that the transmitter does not clarity, and returned a kit.
I have compared the output from a radio and from a bug and could not tell the difference and I have a new $15 hearing aid from China, so I can hear it very clearly now.