Proce rules setting help please

[Devjin]

Hi people so i purchased the plug in recently i got supplier who has given me discounted prices so when i import the products from himi need thw rule to set the price as strictly $19.99 no matter what the cost price is showing up,i tried playing with the rules but could not get it to work,i know i can do it manually but its 300+ Designs to input and was hoping to speed up my work