Adrian,

What level of ordering do you want? A customer fills out a form, e-mails
it to you with a payment and you send it, or one where the customer
orders and pays for something then it is shipped?

If it is the latter, you will need to use something like PayPal or
another shopping cart/payment gateway, which you will have to set up.
Each shopping cart, such as Mal's or PP helps you create a code. Say you
want to sell Widget 1 for $10.00. You would put a picture of it, or just
text with a Buy Now or Add to Cart Button as part of a form. When the
customer selects to do that, the product name, cost, etc., is sent to
the shopping cart. You can also set up the form so that the customer's
name, address, zip code, state, phone number, etc., also are sent.

PP has what is called Sandbox where you can set up a practice site.

Mike