Oatmeal, dried beans, and rice aren't very expensive even at pricy stores. A canister of Quaker Oats is usually around $3-4, and it has 30 servings, a whole month of breakfasts.
A few $10 workout DVD's would likely work just as well as a fancy gym membership, or driving to a place with walking trails to run for a bit of variety.
$300 a month for one person, plus $70 eating out is ridiculous. Why do you need to buy pre-made pasta meals, is it so difficult to cook pasta in a pot, drain it, and add some jarred sauce? I cook for one all the time, and what that usually means is I make a regular sized, or halved, recipe and eat the leftovers over the next few days. Buy fruit and vegetable that are in season. Potatoes are versatile, easy to prepare, and dirt cheap.
What I see in the post is a bunch of whining and excuses why he, or she, can't cut expenses more.