Show me a shopping list that provides 100% RDI of all vitamins and minerals (without dangerous excesses of any of them), a reasonable balance of protein, fat and carbs, sufficient omega3s, and 2000 Kcal/day. You don't even need to worry about making actual meals out of this random assortment of ingredients, just the ingredients themselves. I do not believe you can do it for $230/month.

  Multivitamin ~10$
  1 gross eggs ~20
  30 cans refried beans ~20
  ~100 small tortillas ~7
  5 lbs rice ~5
  3 lbs sour cream ~9
  salt ~.7
  pepper ~1
  garlic ~2
  10 lbs potatoes ~10

spend the remaining ~3/day on whatever you feel like. suggestions include: pasta and sauce at ~1 a meal. whole fat chocolate milk at about ~2 a day. a pint of olive oil a day. a case of ramen a day. a pint of ben and jerry's (there's 2000 kcal by itself).

Prices sourced from an H.E.B. supermarket in Austin Tx. Oh, also, I've been living on less than 3$ of food a day for the last year, so this isn't exactly theoretical. 230 per person per month would the height of luxury for me.

Read the requirements again. You aren't even approaching them.