i can see you can add options for physical products, but this can’t be done using digital?
basically i have two zip files, one is a free version of work, the other is a paid for version. i would of liked for the customer to be able to choose which one they would want for check out. After they have the free version, they can come back and get the full version if they want. can we please add this feature, i cannot think why you wouldn’t already have it as standard. 
thanks.