Tell me how to calculate the cost and release date for an MVP?

MVP has to be defined first. Assuming you have a list of stories that are all groomed and sized, you can combine that with your estimated velocity of your dev team. This velocity should be based on a historical average. If you have roughly 100 points worth of stories in your MVP and you do 10 points of velocity a sprint, you should be done in 10 sprints. You then multiply the cost of the development per sprint (# of engineers @ rate) by 10. That's the cost, but you should charge your margin on top of that. Also, there's always "found" work so you should add 50% schedule slack so it really should take 15 sprints. Underpromise and overdeliver if you can.