Mark loves his deli meat; I'm not a huge fan, probably because I OD'd on turkey sandwiches during college. If the deli sandwich is a favorite of yours, it's definitely cheaper and healthier to make your sandwiches, even if you buy a higher quality organic or anti-biotic free meat, such as Applegate Farms. Protein and fats are good, as we will be talking about soon, so adding bacon not only packs some extra flavor, but it will keep you fuller longer.
Simple turkey and bacon sandwich
*bacon (nitrate and nitrite free--Applegate Farms sells a good "Sunday bacon" for $3.59)
*raw cheddar cheese (Neighborly Farms of VT sells a great one, as do Organic Valley - found mostly at Whole Foods or local Health Food Stores) ($4 for 8 ounces - but it's very flavorful!)
*hummus or tahini
*sprouted grain bread, such as Ezekiel bread,(~$4) or sourdough, such as Nashoba Valley (~$3.19)
Plus any of the following...
*Granny Smith Apple, avocado, pickles, tomatoes
You can get away with about $3 sandwiches, and you know you're eating high quality food!