Much of the cost of using ranked ballots is going to be a one time cost, such as the cost for new ballot counting software and the cost for voter education to introduce the new system.
The best estimate we can do for cost is compare the City of Kingston, which would use ranked ballots in 2022, to the City of London, which will be using ranked ballots in the 2018 municipal election.
Looking at London's projected costs are a good indication for Kingston. However, we would expect Kingston's projected costs to be lower: London has 3 times the population of Kingston and its population has grown at a rate five times that of Kingston since the last municipal election. For comparison, London's 2014 election cost $1.7 million to run while Kingston's 2014 election cost $522 105.
London, with a population of 383 822 has estimated the additional cost for using ranked ballots in 2018 to be $200 000 (includes other factors, such as growth rate, which would raise the cost).
Given the Kingston's lower population and lower growth rate, one would expect the cost to be below London's estimated $200 000.
For more information about the City of London's use of ranked ballots in 2018, go to this article on tvo.org.