You can use a third party store for selling e.g. yahoo store as then you don't have to worry about the hassles of setting up actual transactions. The other option is to have a development company help you out and set up a full ecommerce transaction system for you.
The following things that can be considered before starting ecommerce store,
- Find out Ecommerce solutions providers to design and develop a website
- SEO Services providers to promote your store
- Store Space to handle all products
- Online Payment Solutions
All above are main task to plan before starting ecommerce store.