Based on your description, here is what I propose.
- As you want your website to be ranked in search results, need a cart to sell and payment system, I would recommend to get your site build on WordPress platform. It is very easy to learn and contains all the features you are looking for.
Detailed explanation:
- For ranking in Google, you need SEO done on each page of your site. I would do more than 95% of it while building the site. The rest, I would explain that to you as that would be your part. We would use All in one SEO for WP to make our lives easy.
- To sell Items and to setup payments, we would use WooCommerce and would turn your site into a store where people would be able to buy and to pay you online, securely.
- You will be able to add new products/pages without the need of developer (me, hope so. haha) as I will provide you the CMS to control that.
- For membership levels, we would use PMP pro that would control what user would see based on his membership level.
- I will also provide you a one month's free support to fix anything you see or to modify any part of the site.
For further explanation, I need to the doc you were talking about sir.
Waiting for your response. I would not disappoint you at all sir.