interesting question... I'll answer based on last nights dinner....
let's see....

basmati rice (hard to calculate, 17.00 for 25 lb. bag,used 2 cups) so maybe .50(?)
Thai coconut stir fry.....I'll list ingredients-
1/2 lb. bnlss. chicken sliced-1.00
1 bag frz. broc-1.00
1 can coconut milk-1.79(expensive)
1 onion (? 3 lbs.=1.79)
spices
1/2 c. masaman curry paste-.50
4 carrots(? 5 lbs. 1.99)
misc. stuff (garlic cloves,used up a few old mushrooms,etc)
splash of fish sauce+ 3T GF soy sauce-.35
so about a total of 5.++...??? for 2 adults 2 teens- with enough left over for tonights dinner (yay) =.65 per serving?

hard to calculate some of the 'pantry' items like spices,etc.

night before last was waffles and eggs and oj (yes indeed)
cost for that was
2.59 for the GF bisquick mix (Aldi brand)
1.50 for around 8 eggs used
??? real maple syrup(12.99 for 32 oz jar)
1.39 OJ (Aldi frozen concentrate,mixed up)
so again, around 5-6.00 for dinner+ enough waffles left over for breakfast the next day on the way out the door.....
this is an interesting view of our dinner habits.....makes all our dinners out seem WAY too pricey!