Hilchot Shabbat 30:7-8 (What if you cannot afford special food for Shabbat?)

The law of “oneg Shabbat” requires a person to eat special foods on Shabbat. What should a person do, however, if he cannot afford special foods? And conversely, what should a person do if he always has special foods, and his Shabbat meals are accordingly the same as his weekday meals?