Vegans, in stead of using pre-fabricated burgers, you yourself can make your own burgers : I make hemphu-burgers : I buy a few kilos of hemp seeds, cook the seeds, squeeze out the water with a nettle cloth and make burgers which I keep in the freezer for consumption.
We buy rice and millet in a big bag of 5 kilo in stead of buying different kind of grains in little bags.
Another idea is to make your cereal milk yourself : cook grains like rice in much water, mixing it, add rice syrup and more water, ready is your grainmilk!
Grainmillk can also been made with the help of koji (Koji fungus = Aspergillus oryzae). This koji culture is an aid for the creation of the fermentation process to make rice more sweet.(fermentation on 40-50°) if you add this to your boiled rice, again mixing, add water, et... : another grainmilk is made!
Re-filling bottles of liquid detergent or using washing powder.