I use my slow cooker once or twice a week, and I usually eat some and freeze the rest to eat later. I do cook in it - that is, actually prepare meats and veggies, pre cook where needed etc, but one of the best uses I have found is to "Modify" already prepared stuff. For instance, I buy a couple of packets of dry soup, but I will add stuff as appropriate. For instance, vegetable soup I will add fresh mushrooms, onions, leeks, etc - basically whatever I can get which I think will be OK. I also use dried veggies, and "soup mixes" of dried veggies which thicken it up nicely.
Last week I had a nice beef soup/stew, which I simply made up of Mushrooms, Onions, taters, peppers, and some cooked cut up burgers and gravy granules. So easy too - did it when I had time, flicked the cooker on b4 I went to work, and I have come home to a hot meal for little effort.