I'm Joey and i have 8 years+ experience building and extending ecommerce stores (reviews: https://www.fiverr.com/webappdev).
Your online store and the customizations are on the range $250, $350 (website + 4 add-on extensions), $450 (website + 4 add-on extensions + 3 months free support). Each package is an all in one fee for consulting and implementation of online store from idea to market. All Addons are specially coded into your store so you won't need paid apps saving you hundreds of dollars monthly. I'll advise and help you choose a theme that'll serve as a basis for the project. Then handle some front-end customisations you might want to make to better taylor this to your branding. Your work would be incrementally tested on a minimum of 7 separate devices for conformity and usability. The deliverables include domain name setup, full Setup/Configuration with up to 10 products plus variants and products logical categorization and user manual so you can add products yourself in future if you choose to. Let me know if you have any questions. I look forward to helping you get your ideas to the world.