This may sound much, but seriously, the package is filled till the very top and it´s 1,2kg. it lasts for at least 2 weeks if you eat it every morning and during the day when making actual food would be too much of a hassle.
*milk - woolworths homebrand - 2l cost 2au$
I use skim/light milk, since i like the light taste better, but it´s all up to you.