shopping cart addon

adding shopping cart to an existing web site. would like to add a shopping cart function to a simple html website. i will open an "order now" page, where user will transmit a certain ammount (or by choosing a product) after the transaction will get the approval he will get a sort of "electronic ticket" generated to him, for him to use. the user credit card details will not be saved on the net. my servers are working with windows or linux mysql or access. please describe how can it be done. (remember the html design is already there) thanks,