Forms that have a limited amount of submits

Site URL: https://www.candleloop.com/subscribe

Hi there,

As the title emplies, I want to create a form that has a limited amount of submissions due to the fact this is going to be a free giveaway and I will like to limit the amount of items a customer can submit at the time (no repeated emails) and a limited "stock" let's say 50, yet to figure out how many I am gonna give away.

Also to integrate a countdown clock for the duration of the "promotion". 

Is this at all possible?

Many thanks.