No, Lightning Lane Multi Pass and Lightning Lane Single Pass options are dynamically priced depending on a large number of factors.
Both Lightning Lane options can be added to your account on a day-by-day basis through the My Disney Experience App. The cost for your chosen day will only be displayed when the time window allows you to book your tickets in the app. You do not have to pre-purchase either Lightning Lane option but there are only limited availability of the system which is different for each theme park depending on attraction capacity.