My food budget for one is about $300 a month for groceries. I generally do not buy pre-made or packaged foods and prefer to cook my own meals. I usually make enough when I cook for 3 or 4 meals in order to save time and be a little economical.
Eating in restaurants or cafes is very wide in the range of price and so difficult to compare. You can buy a nice lunch for $6 or $60 here in Las Vegas and even the buffets vary in prices from about $8 to $40, but of course there is a difference in quality also.