I think if you’re going to do business online then you should have a website, but I’m realistic enough to know that not everyone just jumps right in and develops a winning site right off the bat. You want to test the waters first. No problem. You can still sell your items without a website.
Google Base allows you to upload your entire inventory by spreadsheet and you can sell through Google Base. Even if you just have one product you can upload the database and create a Google Base page for that product. Then you have to drive traffic to the web page.
Be sure to let your customers know they can order online. If you don’t have a PayPal account, you can connect Google Base to Google Checkout and send invoices. PayPal is a much better service, but if you don’t have a website then Google Checkout with Google Base is adequate to get you started. But as soon as you start making money, start building a website.