You said she had to pay $0.30, but in the picture it looks like it says she pays $0.33, so I used the 0.33 amount.
The gift card was $50, she had to pay 0.33 cents, so total paid was $50.33
The total for the pajamas and necklace was: 17.97 + 25.49 = 43.46
Subtract that from the total spent to find the total cost of the socks:
50.33 - 43.46 = 6.87 ( total cost for 3 pairs of socks)
Now divide that by 3 to find the cost of 1 pair:
6.87 / 3 = $2.29 per pair