Simple Shopping Cart Plugin for Use with Custom Fields in WP 3.0?

I’m uncertain whether this is the place to post this, if not I apologize, but I’m at the end of my rope.

I’m working on developing an online store for an artistic collective I am building with some friends. I’ve been trying to find a simple shopping cart solution for the site. I tried wp-ecommerce but it’s far more complicated than what I need.

What I’m looking for is a simple plugin to allow me to set the price, name, and stock of a product in custom fields of a given post, and add an ‘add to cart’ button in the template file rather than a short code in the post body.

If anyone knows of a plugin that can do this, a point in the right direction would be much appreciated.

(In addition to wp ecommerce, I tried WP Simple Paypal Shopping Cart and although I was told I could pull the price data etc. in the loop, I wasn’t able to make it work – but it has no support for controlling inventory anyway, so… not so helpful)