Wrap sandwiches using tortillas or lettuce wraps, salads, stuffed tomatoes.  A thermos could hold hot soup until lunchtime.  Here is a Pinterest board with low carb lunch ideas - http://pinterest.com/locarblifestyle/lunches-low-carb/

I try to take my lunch to work every day, it is a real money saver.  I am frankly shocked by how much money my corworkers spend every single day on sandwiches, sodas, chips, coffee, etc.  Plus they always complain about being broke.  Duh.

I usually take leftovers or some form of sandwich.  I try to stay "prepared" by always having bread in the house, and also when I cook for dinners, I cook extra portions with the idea that they will be lunches.   I also buy yogurts and fruit--MUCH cheaper in the grocery store than in the cafeteria at work.  But I am no saint.  I also bring a few cookies, miniature candy bars, granola bars, etc.  I keep stuff on hand in my lunch bag so there's no need to run to the vending machines when I have to have a snack. 

For cold ideas?  Almost any sandwhich, yogurt, fruit, just get an insulated lunch bag.  Also cold leftover chicken, cheese and crackers, hummus, etc.

I have learned that even when I am totally unthrilled in the morning by what I pack, by the time lunchtime rolls around I am always famished and pretty pleased with anything I've brought.  Even the basic PB&J is delishious when 'I'm starving.  And I look at some coworkers and think: ka-ching, I just saved 7 more dollars.

Some good main dishes can be simply a type of bread or wrap plus fillings.  To make it easy, think "sandwich" with a different kind of bread--pita pockets, tortillas, bagels, biscuits, flatbread, English muffins, even dinner rolls split in halves.  Or skip the bread and have crackers with meat and cheese, like your own homemade Lunchables. 

If you can afford a nice thermos, consider hot soups or stews, chili, or even casseroles; you can even pour boiling water over hot dogs in the thermos, and by lunchtime, they are nice and warm all the way through.  Other good options for serving cold are: salads (just put the dressing in a separate container), hard-boiled or deviled eggs, and cold pizza (especially homemade!).  Someone else mentioned cold fried chicken, but also try leftover bbq... mmmm!

Sides could include: fresh fruit, veggies, rice, beans, or noodles, gelatin or pudding, salads, cheese cubes, crackers, chips, pretzels or popcorn.  Desserts are easy--muffins, cupcakes, donuts, cookies, brownies, candy bars, fruit tarts or homemade fruit "pockets" (like a folded pie) are all yummy choices.  You can even bring a slice of pumpkin or sweet-potato pie if you plan well so it doesn't get squashed.  ;-)

HTH!

You might try this link for pintrest http://pinterest.com/easylunchboxes/

I follow it to get ideas for lunches   I do a variety of feezer cooking and put the servings in individual portions for lunches.  There are several things that freeze well.  Do your kids have a microwave in their lunchroom? 

Thanks for the link, Vitallia, I am a Pinterest fanatic.