If you can afford it buy a list of ecommerce companies. If you want to stay lean source your own list. InternetRetailer.com is likely a good place to start.

Also data mine LinkedIn and use Inmails or tools like https://salesloft.com/ to contact the marketing leads at ecommerce companies.

I would segment my data mining activities based on your perceived sweet spot. Look at the ecommerce companies by their:
- sector
- revenue
- number of employees
- geographic location
- etc.

Reach out to them via LinkedIn and email with some specifics. Look at their site, current ppc efforts, etc. Give them some free insights.

Good Luck! I'm happy to hop on a Clarity to call to go deeper here.

- mike