But while some planning and a little work is needed, stick to cheaper proteins (chicken/pork), vegetables, and things like rice/beans and home cooking, even for one, can be pretty inexpensive and doesn't need to mean eating the same leftover stew for a week.
I do think a lot of "cooking at home is too expensive" is actually "I don't want to cook at home and would rather just get takeout."
ADDED: And especially if you relax the cost constraint a little bit, there are a ton of meals I can make from unprocessed or minimally processed frozen food in about 15 minutes from freezer to table. Less than $10 for a meal is trivial--and can be significantly less than that.