Once you get in the habit of taking picnic food in the car it's quite easy and you won't waste so much time sitting in restaurants, either, in addition to the cost savings.
Why not keep a plastic, lidded tub in the toad with, say, a box of Triscuit (reduced fat taste better than original for some reason), cannister of almonds or dry roasted peanuts, cannister of raisins and whatever other shelf-stable items appeal to you. Paper plates, napkins, wipes and cutlery can also live in this box along with basic condiments.
Then, just use zipper bags or washable food containers to take an array of items such as pickles, olives, sliced veggies, cheese cubes, rolled lunchmeat, jerky, etc. Ranch dip is sold in single-serve tubs and with a piece of fruit you have a nice picnic. You can make up lots of baggies of the items ahead of time, with perhaps some Chex Mix or a small handful of pretzels, and with so much protein you'll stave off hunger all day.
Hardboiled eggs, sandwiches, small tubs of chicken salad, potato salad. Pre-cook bacon and take along ingredients for a "BLT." Green salads travel pretty well in a cooler.
If you have a vacuum jug, take along warm baked beans or soup to drink out of cups.
Even if you don't pack a lunch, nipping into a supermarket deli for a couple of items -- french bread, sliced turkey and a jar of pickles, for example -- is way cheaper than dining out and better for you. Take a gallon jug of water and paper cups so you aren't tempted to buy the plastic water bottles.
