The cheapest sandwich on the list, predictably, is the classic bologna. This depends on the type of ingredients you use, naturally: organic whole-grain bread and the fanciest bolognas will bump up the cost just a little bit. That applies to all sandwiches, though. Or all food.
The bacon-crazed Internet will be sad to learn that the bacon, lettuce, and tomato sandwich comes in as the second most expensive. Sad, but not surprised: after all, it includes both bacon and fresh vegetables. The most expensive sandwich is the tuna salad sandwich.
The cost per sandwich depends on a few other factors, though: like what you consider a “serving.”
Penzo calculates that he saves $500 a year by packing lunches for his kids, and also gets to serve them something healthier than the trays his kids’ school is charging $2.75 per day for this year.