Of course, it's cheaper to cook at home. But the McChicken is, like the whole industry that is to blame for it's existance, a serious threat to our physical health and thus to be avoided at any cost.
Over a lifetime it's more economical to not eat any fast food.
The fast food you eat on a regular basis early on in life just degrades your health later on in life when you will spend money trying to remedy. You will pay for that fast food twice, once when you eat it and again later on life when you pay to treat your heart, weight, circulation, blood and inflammation.
Eating fast food is investing in having some terrible last years of your life .... you may live long but if you're not healthy now, you'll spend the last ten or 20 years of your life miserable.
If you’re eating it on a regular basis sure, McDonald’s once every two weeks or longer isn’t going to kill anyone more than the rest of the junk on the shelves