what approach/module in joomla should I use?

Question

Hi,

Here's my need. I'm building a site that let users add product to a list (something like a wishlist without a cart). Now my question is, Is there an existing extension in Joomla (1.5) that do similar thing?

Another Is calculating the total cost of the product and calculating other factors, like discounts, freight, weight etc.

I am think it should be module so I can easily change the position of the extension.

Let me know if you got some Idea with other approach.

Thanks! :)