Create A Shopify App Or Customize An Existing App

I need someone to either create an app or use/setup existing apps to add a few features to my Shopify website. Primarily, I need to modify the structure/options of how the product's prices are displayed on the webpages and the options on how the customer can pay. You must be ready to prove that you have completed similar Shopify projects recently. More details will be provided to bidders via PM