If Winona and Takoda buy the power tools, the cost is \( d \) and the discount is \( 15 \).
The total paid for the power tools is:
\[ \text{Total paid} = d - 15 \]
Thus, the expression for the total paid for the power tools is:
\[ d - 15 \]
This is the only expression needed since they only have one present (power tools) being considered.