(i) To create a stem-and-leaf diagram, separate the thousands and hundreds (stem) from the tens and units (leaf) for each price.

Sort the prices: 14 300, 15 300, 15 400, 15 500, 16 100, 16 400, 16 800, 16 800, 17 300, 17 700, 18 500.

Stem-and-leaf diagram:

Key: \(14 \mid 3\) represents \(14300\) dollars.

(ii) To find the lower quartile (Q1), arrange the prices in ascending order and find the median of the first half.

Sorted prices: 14 300, 15 300, 15 400, 15 500, 16 100, 16 400, 16 800, 16 800, 17 300, 17 700, 18 500.

The first half: 14 300, 15 300, 15 400, 15 500, 16 100.

The median of the first half (lower quartile) is 15 400.