Hi Geoff, if it is just you involved, then setting up as a sole trader is the easiest and cheapest option available to you for sure.
The big difference between a sole trader and a company structure, apart from the cost and taxation reporting styles being different, is the liability.
As a company structure, it's the company that holds the liability, as a sole trader, it's you and only you.
e-commerce (electronic commerce) covers any online trading business, so from what you have written above, yes, you would be involved in e-commerce.