Allowing Someone to Order an Item Once Their Cart Reaches a Minimum

[TerryPullen]

Hi, 

Does anyone know if there is an app that lets someone add an item to their cart for purchase (not a free gift) once their cart reaches a minimum?

For example: We have an item that is $4. Once a customers cart reaches $25 they can add that $4 item to their cart to purchase. 

Thanks!