If selling goods online, you're not going to get very far without a shopping cart. Before going any further a common misconception when it comes to shopping carts is that they perform the whole purchasing process - from ordering your product to your money being sent to the seller. Unfortunately that is not what occurs with most shopping carts as they're primarily used only as a front-end interface. What this means is, you can search through products and even specify what you want to purchase but no actually ordering can be done unless a "payment gateway" is set up.

A payment gateway is a service that allows money to be sent and received. Some websites will provide both the shopping cart and the payment gateway together; some will just provide you with the shopping cart interface and some services like PayPal offer a service which allows anyone to set up a payment gateway combined with a simplified shopping cart in a matter of minutes. The type of solution you choose will depend on what you require for your particular business but regardless of your choice, there're certain factors you should think about so you can choose a shopping cart that's right for you.

Scalability

A good amount of research is required on your part before you go spending money on a payment solution. Will your business still be around in 3 months time? Are you willing to take a gamble and spend more money than you possibly need to? These are some of the questions you will need to ask yourself. Check whether your shopping cart service allows you to change plans midway through and any other appropriate details.

Payment Compatibility

There're various types of payments one can purchase an item online with. You need to work out which types you're willing to accept and whether or not your shopping cart can accommodate them.

Support
You should investigate whether or not your shopping cart provides any technical support just in case you need help with installation or any other issues.

Hosting

An important issue to many is whether or not they have a choice of where the shopping cart is actually hosted. Some services will only allow the shopping cart to be hosted remotely, basically giving you no control if things go wrong. Others will allow you to host the shopping cart yourself on a local server leaving it up to you to manage the account.