Implement a simple Guess Game with connection to wordpress database

I’m assisting in developing a website that will have a simple guess game on it. Every week there will be a sponsored coupon available and each member of the site is able to make a single guess each day on the value of the coupon. If they get it right, they receive the coupon and 1 of the quantity of coupons available will be removed. This will continue until the end date, or all coupons have been won.

Now the code behind it I can do in Javascript, C, C++, anything like that. But how can I implement this using the wordpress systems, or is there any plugins (free or paid) that I can use to implement this type of system.

Thank you for any help with this.
Daniel