Processing credit card payments through a web site can be accomplished in a number of ways.
Many people are familiar with the PayPal Button, which was one of the first implementations of a secure payment system. It is generally considered older technology and has a history of failed dispute resolution with sellers. It has the advantage of being low-cost and simple for small number of transaction types.
E-commerce / Store-front templates. There are a number of web-companies who have templates designed to work with back-end processing systems. They offer sub $1000 packages that do NOT include setting up ANY of the financial transactions support accounts. These are generally referred to as merchant accounts, with you are responsible for establishing with the various card processors. Most companies selling these services are focused on equipment for retail stores. They generally charge a setup fee (100$), a per-transaction flat charge (.25), and a percentage of each transaction (1.5-3.5%) based on the volume of transactions you perform. Many require a minimum monthly charge in the $20-25 range if the processing charges do not reach the minimum.
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