Cooking for yourself is the best way to watch what you're eating and how much you're spending on it.
It's also a time commitment, both in developing the skills, and also selecting menu items and shopping.
For most people the benefits of the former combined with the development of a highly useful life skill are worth the time commitment.
This is true even for single folks.
Certainly over time you will build up both an inventory of spices and other stock ingredients.
In addition, you will compile a mental shortlist of menu items, complete with good uses for leftovers. Not just reheating, but reuse.
For instance, roast potatoes can easily be reheated and remain tasty, both for another meal as well as acting as home fries with breakfast. Meats can be thrown in as an ingredient for burritos. Egg rolls can be made with leftovers, and stir frys work well with left over rice in addition to other ingredients.
There are numerous threads on simple bachelor cooking over the years. Here is one from the El Diablo forum:
The Official Professional Bachelor Food Suggestion Thread