The equation \( y = 0.19x \) describes the cost of pencils, where \( y \) is the total cost and \( x \) is the number of pencils. To find the cost of one pencil, we can set \( x = 1 \):
\[ y = 0.19 \times 1 = 0.19 \]
Thus, the cost of one pencil is $0.19.