Getting started requires more than one product, or even one company to do business with. For a fully successful end of the day sales, you need to carry many items, from many different distributors. You need to take their disorganized mess of products and updates, and convert them over to a master list in excel so that it can be uploaded to your store in one batch. Additionally, for maximum sales, you need to sell anywhere you can find. This means selling on eBay and Amazon. Ideally, you should have multiple accounts on each (in case one gets negative feedback, suspended, etc).
This means that you need a master list in a format your own website understands, one that Amazon understands, and eBay understands. It requires quite a bit of data entry to get all the various systems to have the same items. Then it requires daily updates with discontinued and out of stock items. All this is on top of orders, returns, and daily headaches. Properly selling on the internet is definitely not for the faint of heart. It takes many long hours.