These things go hand in hand, the biggest reason to pay the large premium on prepared food is that it solves logistical problems, which you will likely have more of if you suffer from poverty. I started the dough to make pizza half an hour ago which is going to end up as several very inexpensive meals, but I had a childhood where I was shown how to make pizza, I have a kitchen to myself, a relaxed day where I have plenty of time and energy to prepare food, and enough financial stability and space for planning to buy all the ingredients at once in advance in bulk quantities. I've known people who went into debt to buy pizza, and they lacked all of these things.