You can get that result through an studio approval, follow these steps:

Open up studio on your purchase module

Click on the confirm button and on the left side you'll find a gray column with something like add approval steps

Click right there

then click here and it should open up a new menu like this 

Click on the new button which will open up the form where you can set the parameters for your requirement

On the domain you'll be able to set a rule for the amount