If I have a 4.396 GPA at the end of my junior year, is it worth taking a summer class going into my senior year to increase my gpa to a 4.400? Does a 4.4 look a lot better than a 4.39?
If the sole reason for taking a summer class would be to raise your GPA from a 4.39 to a 4.4 that would be a complete waste of your time, energy, and money. Find something more valuable to do.
Also, no one knows the scale of your GPA system.
Nobody would care about a 0.01 gpa difference. You are waaaayyyy too stressed. Relax a little, that doesn’t sound like a bad gpa 
Work over the summer so you have spending money for the great college you will go to.