The beauty of WordPress is that it brings traffic to your site if you post good content frequently- and if you want to sell stuff, traffic is good.

The problem with Shopping carts online- is they are only that – a shopping cart- a store, with no advertising- except what you pay for. Magento is an amazing open source shopping cart solution- but, it’s not a CMS- and it doesn’t give you the ease of posting that WordPress does- so- enter Visser labs- with their plugins that bring the WP e-Commerce plugin some of the cool functionality of Magento- without the the complexities.

The first is the ability to have 2 different price levels- one for wholesale- and one for retail:

Wholesale Pricing for WP e-Commerce uses custom User Roles to apply different pricing levels against preferred customers (e.g. Subscribers, Wholesalers, Staff, etc.).

via Wholesale Pricing | Visser Labs.

Another gives you the ability to do wish lists:

Add to Wishlist for WP e-Commerce also allows WordPress users to manage their Favourites entries and remove items they no longer desire. Easy integration to WP e-Commerce and comprehensive step by step instructions are included.

Or offline credit card processing- for those who don’t want to charge when ordered- but when shipped:

Offline Credit Card Processing allows store owners to process credit card orders offline by accepting the credit card information and spliting the card number into two parts; partial save to the database while the rest e-mailed to the store owner.

Check out their site for more plugins to this e-commerce solution for WordPress.

While many bloggers are cashing in on paid advertising and affiliate fees, the options for setting up small shops is limited by “plugin” store solutions. WordPress is great for building community, the ideal way to target your customers, but when it comes to adding a simple solution you are limited to the three main options available now:
MicroShop
by Owen Winkler (RedAlt) which is currently down. It is the shopping cart I use on Websitetology. Current link: http://www.websitetology.com/wp-content/uploads/microshop.zip
Paypal or checks only, it has some issues with data entry in the phone field, and has limited tax, shipping, and notation options.

Note: June 08 This solution was pre WordPress 2.0, it’s highly unlikely that it still works.
WP-Shop
http://cregy.net/small-business-software/wp-shop/
Last time I installed this, there was no payment gateway. It was the nicest integration of the three, but without checkout, it was worthless. Since I haven’t tried to use it since June, I can’t tell you what the status is now.

UPDATE: June 08, this plugin seems to be abandoned.
WP e-commerce lite
http://www.instinct.co.nz/e-commerce/
We’re using this on www.londonbaystationery.com. It has no way of setting tax per order, or shipping charges. The only included gateway is PayPal, for a fee you can add authorize.net and dps.co.nz

UPDATE: Jun 09 This plugin broke again with 2.8. It’s been a constant headache.

We broke down and purchased the Shopp plugin http://shopplugin.net/ it works flawlessly with 2.8.

We also looked at e-shop, http://wordpress.org/extend/plugins/eshop/ but, we failed to rename the product page, and were in limbo for a while. It requires a page per post, which may or may not be a graceful way to handle things.

E-commerce with a WordPress shouldn’t be that difficult. While most of these solutions are limited to using WordPress with a PayPal solution, the ability to use other payment processors like 2checkout.com or google checkout should be available. WordPress is the easiest way to build a community- so shouldn’t it be just as easy to sell to your community?
A more complex option is to build a ZenCart site and add a WordPress blog to it with this module:
http://zencart-module.s-page.net/index.php?main_page=product_info&cPath=2&products_id

JUNE 08: Another open source option that looks good for a cart is Magento: http://www.magentocommerce.com/features

There isn’t a WordPress module- or integration- but, it’s getting rave reviews as a well written piece of code.

There must be other shopping cart plugins out there- but this is what we’ve found. If you have any others, please leave a link in the comments.

UPDATE: Jun 09 found this link with 10 shopping cart tools for WordPress  http://speckyboy.com/2008/10/23/10-powerful-shoppingecommerce-plugin-solutions-for-wordpress/

UPDATE: Apr 8 2010: Here is a comparison chart of carts: http://www.briggs.net.nz/log/2009/09/13/warts-and-all/