Either an Amazon store or an eCommerce online store using dropshipping.

Pro's and cons. With an Amazon store you have already got traffic of millions and millions of customers using the site 24/7, so not very much is needed in terms of marketing as the platform already exists. Although the platform will always be Amazon so although you can generate a lot of revenue using their site, it's never going to be your own site. However, you can change your product range to fit with trends etc and people aren't really going to know what you're up to (or care).

Launching an eCommerce store (whether it's dropshipping or not) would take a hell of a lot more work as you're building it literally from scratch. But if you did it right it's going to be your own established website that you own, unlike Amazon. It's probably a bit more difficult to chop and change your product range on an eCommerce store because if you launch a fishing site for instance, you're limited with what you can advertise (I'm pretty sure I'm probably wrong here though and the website host can help change and edit your site to fit with your needs).