On Fri, 19 Oct 2007 22:46:54 GMT, I wrote:

>An 8 oz cup of yogurt costs $0.89 and will start two batches before it
>gets old. Cost per batch: $0.45.
>
>A box of starter contains six packets and costs about $3.00. Cost per
>batch: $0.50.
>
>It's not enough difference to matter -- unless I find that I can make
>yogurt with less than a whole packet of starter, which would make the
>starter considerably cheaper.

I now have made two successful batches, about a week apart, with the
two halves of a packet of starter. That cuts the starter cost to
$0.25.

Next I'm going to see if I can make a batch with 1/3 packet of
starter. This is in the spirit of scientific inquiry -- $0.25/batch
is cheap enough that further economy isn't important.