Here is the simple way I have found to sell affiliate products in your Interspire Shopping Cart store.
First, get the code that your affiliate provides you to add the affiliate products to your website.
Next, go to Add a Product in your Interspire admin panel.
Click the “HTML” button above the box where you type in the product description:
Paste the code from your affiliate into the window that pops up.
Scroll down in the pop up window and click the “Update” button.
You should now see the affiliate product in the Product Description box.
If there is an image for the product, right-click it and save it to your computer. Then delete it from the Product Description and add the image as you would add an image to any other product in your store.
Copy and paste the product name into the correct field, put the product in the correct category on your site, and add the price to the correct field.
Once you have the product listed the way you want, scroll down and UN-check the box next to “Allow customers to purchase this item.”
Save the product and go look at in in your store. It should look just like any other product you would add to the store, except that in order to purchase it, people have to click the affiliate link which you pasted into the product description (this way their clicks from your website to the affiliate site will be tracked, since you are using the code that the affiliate site gave you).
Let me know if you have any issues with this or any questions about it.