There are times when I purchase meat from the butcher when it is available and at a good price. Other times I purchase from the supermarket. When you get meat from the butcher you can specify how many lbs of ground you would like per package.
To package meat from the supermarket on trays, I get a large bowl and stack all of the meat trays up beside the bowl, then place the trash next to me. I wash my hands and open the first tray, throw the plastic wrap in the trash, and dump the ground meat into the bowl, then place the Styrofoam tray in the sink. I continue this until I have opened all the trays. I wash my hands, rinse off all the trays and run a sink full of hot soapy water for them to soak in. Wash my hands again.... and set out sandwich size plastic seal able bags. I set one on the kitchen scale and fill it with ground meat until it weights .75 lb. I continue filling bags like this until all the meat is used. Then I wash my hands again.... I squeeze the air out of the bags and then seal them and flatten them down so they will store in the freezer flat. Next I clean up the counters with hot soapy water, wash the large bowl well, and wash the trays well. The trays make excellent paint trays for kids or crafts. I have found that I do not notice the difference between using a 1 lb. of meat vs. .75 of a lb. If it is a dish that needs a lot of meat like meatloaf I will use two packages.