What discount apps can offer 20% off on the most expensive item online?

[ES-LT]

A common sale we run in our physical stores, is 20% OFF any one regular priced item (usually the most expensive in the cart). Are there any Discount apps which allow a discount code to work this sale in our online store?

I'd also love an app which works for POS, as our current procedure is to have the employee at the register manually mark down an item and human error is a thing.

Thanks

[CircleCreations]

Great question, I'm also interested in a solution to this one, it seems like a pretty common offer, I'd like to use a lot.