Still having trouble with my Nissan maxima 2002.


I kept needing a jump . My car kept going dead. So I went and bought a new alternator and battery. The new alternator was put in 3 days ago. The dude that put it in . Said that the battery was so fried. The cells were fried. So I took it to walmart. And they looked at the battery and said. It is completely fried. So they replaced it with another new battery. Now today the car needed a jump again !!
A couple times. At a red light it would shut off. Or going slow/turning a corner. The car would slowly die out.
What could be the issue ??
New altenator, new battery ! Still Having Trouble .
Could it be a short in my car? The electrical problems? Please help
I'm a single mom and this is my only way of getting around. I know nothing about cars. I don't want to take it to a shop and get totally ripped.

Any suggestions?