Unfortunately there is no single answer to this question.
There are simply just too many variables to take into consideration, it’s a bit like asking an estate agent how much do houses cost. Without knowing the precise requirements, ie: how many bedrooms. bathrooms, semi or detached, etc etc, it’s simply impossible to answer.
So, How to Proceed?
Have in mind a budget that you would be prepared to invest, then double it.
Honestly, a well produced corporate video will not be “cheap” but, will provide a good ROI