A shopping cart is a program that runs on your web server . As customers browse your website, they can click on items they wish to purchase. The shopping cart program will add the cost of the items together like a cash register and when the customer is ready to complete their purchase, they will be prompted to fill out a form with their credit card and shipping information. The cart will calculate shipping and taxes and total their order. It will also send them an email confirming their online purchase.
Websites vary greatly in price depending on size and complexity.
Please look through my portfolio and if you see a site that is somewhat similar in size and function to the one you wish to build, I can give you a quick estimate. After discussing the details of your project, I can give you an estimate of what your site will cost and answer any other questions you have. This depends on the size of the project. I can have a small site up and running for you in a week, a medium size site might take a month and larger sites will take longer. You can speed up the process by having all your images and text ready for me.