The best ecommerce model for a low margin and high volume online store is the marketplace model. This model allows businesses to leverage the scale and reach of established online marketplaces to sell their products. By listing products on these platforms, businesses can tap into a large customer base and benefit from the marketplace's marketing efforts, customer trust, and infrastructure.

Here are some key reasons why the marketplace model is suitable for low margin and high volume online stores:

1. Increased visibility and customer base: Online marketplaces like Amazon, eBay, and Alibaba have millions of active users who visit these platforms regularly. By listing products on these marketplaces, businesses can gain instant visibility and access to a vast customer base, which is crucial for high volume sales.

2. Cost-effective marketing: Marketplaces handle significant marketing efforts to attract customers to their platforms. This reduces the marketing costs for individual sellers, making it an ideal option for low-margin businesses. Additionally, marketplaces often have advanced advertising tools that sellers can use to promote their products within the platform.

3. Established infrastructure: Marketplaces provide a ready-to-use infrastructure that includes payment gateways, logistics, customer support, and order management systems. By utilizing these existing systems, businesses can save time, effort, and costs associated with building and maintaining their own infrastructure.

4. Customer trust and credibility: Established marketplaces have built a reputation for reliability and trust among customers. This trust can significantly benefit low-margin businesses as customers are more likely to make purchases from well-known marketplaces compared to lesser-known individual online stores.

5. Competitive advantage: Marketplaces often offer features like customer reviews, ratings, and seller performance metrics. By consistently providing excellent products and customer service, businesses can build a positive reputation and gain a competitive advantage over other sellers on the platform.

Examples of successful marketplace models include:

1. Amazon: Amazon is one of the largest online marketplaces globally, offering a wide range of products from various sellers. Businesses can list their products on Amazon and benefit from its extensive customer base, fulfillment services (Fulfillment by Amazon), and advertising options (Amazon Advertising).

2. eBay: eBay is another popular marketplace known for its auction-style listings. It allows businesses to sell both new and used products. eBay offers various selling formats and tools for businesses to optimize their listings and reach a wide range of customers.

3. Alibaba: Alibaba is a leading business-to-business (B2B) marketplace connecting manufacturers and wholesalers with international buyers. It provides a platform for businesses to sell products in bulk and access a global customer base.

References:
- Amazon Seller Central: https://sellercentral.amazon.com/
- eBay Seller Center: https://pages.ebay.com/seller-center/index.html
- Alibaba.com: https://www.alibaba.com/