It depends!
If she really needed it, and had the cash to spare- then no big deal. We all have a personal threshold for ammo and real needs certainly push it up a bit. If she bought it just to pad a stockpile then I'd say she overpaid but I'm not in need of 5.56 ammo and my personal threshold is much lower.
First place I looked had 6 options between $0.51-$0.56/ea. https://outdoors.natchezss.com/products ... sort=price
If she needs enough to get free shipping then shop around... if she only needs a box or 3- buy local as she did.