I got one of these about 10 years ago. Still good. It takes awhile to heat up chilled food but you can just turn it on a few hours before mealtime & it's good to go. It doesn't heat up so much that it overcooks your food.

It goes great with these (you can get a few for a bit cheaper for each)

Just put your meal into the little casserole dish, throw the whole thing in the bag, lid & all, plug it in, & you're good. Bang for your buck is certainly much better than a truck kitchen!