Soup in a can (take a bowl) if you have access to a microwave and water, and if you will eat it. Also most sandwich type stuff can be made on a soft tortilla to offer variety. My DH loves 'build a taco' but it is a bit more work, he can easily freeze the meat, but then he takes a little container of cheese and one of BBQ sauce, and a tortilla. But the work is all the night before. (We don't like what freezing does to the shell)
Salad he likes but we had to get a tupperware fridge thing, it is blue and has riged bottom and holes in the side that open or close. It keeps the lettuce from turning brown. I hate brown lettuce. But for he health of a salad and the money savings when lettuce is cheap we think it was worth it. (pack dressing seperate)
Also the make little pizzas at our grocery store, so if they are on sale about 69cents, way cheaper than buying. And some burritoes, I don't like them but DH does, around 50cents he eats two so a buck for lunch. Heh and we feel guilty if he has to do that to often
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Breakfast foods, generally in my opinion eggs do not keep (not to meniton we eat a dozen for dinner so I don't want to cook any more!) but pancakes and waffles do keep, and so long as you nuke them with butter they are very good. (syrup on the side)
On the card thing if you feel too tempted to use it, if you don't have to 'badge in' leave it at your desk, or if possible in the car, or eat in the car, summer is comming to make that easier. Also one thing that helps my DH is he eats at his desk (he doesn't get a lunch break so he is allowed) Or if it is a magnetic thing you could see if you can tape it or something so you can't use it without a lot of work. (again don't use if you have to badge in to your office)