Internode charges a 35c flagfall and 90c per minute (in 30 second blocks) for calls to Australian mobiles, fixed lines and special (13, 1300, 18 and 1800) numbers, and 25c per SMS to Australian mobiles.
Excess charges apply for voice, text and data.
By comparison, Amaysim (which also uses Optus) has a $19.90 plan that provides "$19.90" of credit charged at 9c per minute for voice calls and 9c per SMS, which the company points out is "up to 220 minutes of standard chat or 220 texts (or a combination of both), plus 500MB of data and "unlimited national access to Facebook, Twitter and more".
Assuming five-minute calls (to account for the flagfall), the $20 NodeMobile plan gives over 460 minutes or 1800 texts, as well as three times as much general data.
One issue is that the plans are only available to Internode's fixed-location services such as ADSL, fibre, or NodeLine.
Another is that while other mobile operators charge as little as $2 for a SIM, that little piece of plastic costs $10 plus $5 delivery for NodeMobile. Still, that's a one-off cost that could potentially be recouped through lower ongoing charges.