To find the price per cup of sour cream, we first need to convert the 2-quart quantity into cups.
Since there are 4 cups in a quart, a 2-quart carton will contain:
\[ 2 \text{ quarts} \times 4 \text{ cups/quart} = 8 \text{ cups} \]
Now, we know the total cost of the carton is $7.04. To find the price per cup, we divide the total cost by the number of cups:
\[ \text{Price per cup} = \frac{\text{Total cost}}{\text{Number of cups}} = \frac{7.04}{8} \]
Calculating this gives:
\[ \text{Price per cup} = 0.88 \]
Therefore, the price per cup of sour cream is $0.88.