To change the price of an item you'll need to contact the Codester support. Sellers (or authors) can not change the price once the item is accepted after upload.
Codester Support:
https://support.codester.com/
However, I would strongly suggest not going too low. As a freelancer (im assuming you're a freelancer?) you need to know your worth. $5 for products in the niche you offer is EXTREMELY cheap. Don't do that.
Another option you have is the "Flash Sale" offer. This feature would discount the price by 50%, and I believe this would be more beneficial to you. You will also get an achievement trophy on your profile to let other users know your item was part of a flash sale, and this could potentially result in more earnings and exposure for you.