There are several things to consider in planning a Joomla ecommerce shopping experience.
Where does your customer pay?
If you have a shopping cart extension, they can checkout and stay on your site. A 3rd party solution (like Paypal, or Google Checkout) will send them off site to pay.
Conventional wisdom as Nicholas outlines in his Joomla Magazine article says “The first reaction to the different visuals is â€œwhere did the e-shop site goâ€. Even if they get past this first shock â€“ presumably because you made it very clear on your checkout page that theyâ€™ll be redirected to an external site â€“ they are confronted with a less-than-optimal experience.”
I think that this wisdom however, is a little dated. The web changes fast and today’s online consumer is perfectly happy with paying via Paypal and its a trusted name in ecommerce. In fact, its know so ubiquitous that using it probably helps your credibility. This is evident in the JoomlaJunkie post where a customer says “PayPal is an excellent way to pay on the net. Now I actually choose websites with the paypal facility over those that havenâ€™t got it.”
Who Has the Credit Card Number?
You might not realize, but there is tremendous risk in handling credit card data. Its not unheard of for self-hosted shopping carts to actually retain and store credit card numbers and customer information. Needless to say that this is a massive risk for you to be assuming, one with the potential to wipe your business out in claims and fines if you have a major security breach.
The Payment Card Industry Data Security Standard (PCI DSS) dictates standards for the security of this information. You might not even know that you need to conform to it, but store card information and you probably do. Its also immensely burdensome and expense to implement a system that meets these standards.
Use a 3rd party provider and the risk is all theirs. Sure, they might take a cut of the action with a percentage of your revenue, but that sure beats losing your home in a security disaster.
What are You Selling?
If you have a big inventory, and its you are generating significant revenue online, then you probably need a full blown shopping cart. But if you just have a few items, then there are many solutions where customers can select products and then checkout off-site. Paypal Buy Now, Amazon checkout, Google Checkout or e-junkie are all systems that are on a separate site, and you embed on your site.
Do You Need a Different Hammer?
I have said many times in presentations that there is a big temptation with Joomla, its such a good hammer, to treat every problem as a nail. Ultimately though, you should carefully consider all your options for a particular problem. If you do need a big online storefront, then is a content management system the best option? You might be better off with a full-on shopping cart, and run your Joomla site in parallel. You see more and more sites doing this where shopping is done on a seperate sub-domain, shop.blahbllah.com, and is merely skinned to match the global graphical theme.
So when planning your Joomla ecommerce implementation, be prepared to think outside the box, and be aware of all the benefits and risks involved.