Well, yes. However if you are already a good programmer then it will not take that much time, and if you are looking for a job then there is nothing wrong in expecting that you would prepare. And I would argue that it's not sunk time either. In my day to day job I do not use that many algorithms because most of the actually needed ones are hidden by the internals of the language, I got rusty and the refresher was useful.
Free only if you discount the cost of your time.