A) A good scale is for one square to equal 5. The graph would be less than 15 squares high if starting from $100.
B) A good interval to use for the y-axis is 5, starting from 100. 110 and 170 are both multiples of 5. The range of the data is 60 so we are dealing with a fairly small range which allows for a smaller interval. A graph using 5 as the interval would be more specific than 10.