Responsive Shopify E-Commerce Website -- 2

I need a seasoned web developer to turn my business concept into a fully-functional Shopify store. The site must be lightning-fast, intuitive to browse on any device, and follow modern best practices in HTML, CSS, and JavaScript for clean, maintainable code... (Budget: $250 - $750 USD, Jobs: CSS, HTML, JavaScript, Payment Gateway Integration, Shopify, Web Development, Website Design, Website Optimization)