MERN Marketplace - Connect React Frontend to Backend ++

Need a Mern marketplace. Can use Ghostjs or other headlesscms for backend. Connect frontend template, add favorites and add chat. Understanding elasticsearch auto generated Serarch UI. For chat can make own or add spectrumchat or simiilar. Currently have a backend and frontend sample for qualified applicants. Need to add Stripe subscriptions. Nextjs or gatsby preferred. Please post estimated project cost. Can pay by the hour or project.