There is currently no "Google-like" RDF repository that offers you free access to the whole Web via a convenient SPARQL endpoint.
Some public SPARQL endpoints offer a moderate amount of such data, e.g.
If this does not meet the needs for your application, you will have to crawl and cleanse the data yourself, e.g. from
Note that crawling crawling, cleansing, and consolidating structured data at Web scale is a non-trivial task, so do not expect someone else to do it for you for free. It may be a good business idea to offer such a service.
None of the currently known free and public SPARQL endpoints provide a sufficient coverage and currency of e-commerce data to power serious e-commerce applications.
You will have to do that on your own if your business idea requires that.
Setting up your own SPARQL endpoint
- Virtuoso, EC2 or other cloud services