The Gold Cart comes with some impressive, and in some cases, necessary features. However, there are additional modules available that unlock features above and beyond those of the Gold Cart. If you want access to them, you must buy them individually.
Of the additional modules, the most notable (and expensive) is undoubtedly DropShop. When enabled, DropShop adds an elegant AJAX shopping cart to the footer of your WordPress shop. Customers can add items to the cart simply by dragging and dropping them there:
DropShop is certainly impressive, but so is the price, which is currently $100. You must already own the Gold Cart in order for DropShop to work.
Most of the other available modules serve a much more specific purpose, and all of them are comparatively less expensive. These additional modules include:
MP3 Audio Player— useful for a music store owner who wants to provide previews of audio files before purchase. The current price is $10.
Product Slider— adds a scrollable display unit for quickly browsing through a number of products. The current price is $25.
Members Only— useful if you want to charge for private access to posts, pages, galleries, podcasts, or forums. The current price is $25.
NextGEN Gallery 'Buy Now' Buttons— for use in conjunction with the NextGEN Gallery plugin (adds a 'Buy Now' button to each image in the gallery). The current price is $10.