How can I set a maximum discount amount for student offers?

[CJ-Mojoactive]

We are offering a student discount on our store, but would like to set a maximum total amount. For example, students would receive 50% off up to $1000. We've found several apps that handle discounts, but none that allow you to set a maximum up-to dollar amount.  We worry that the system could be abused without a maximum limit. 

[Ashley_Ta]

We are in bed of this also with no situation from Shopify.