I'm going to try to explain what I do to reduce waste but I'll warn you - it sounds backwards.
I buy more than I need.
Yup.
If my pattern calls for 2 1/4 meters (or yards), I round it up.
That way, I know the piece I have over will be big enough for my stash. And I don't worry about the 1/2" strips that end up in the trash.
The cost of my craft I guess.