Shopping Cart–simple

I am looking for a plug-in that will:
1. add 2 paypal Buy Now buttons to the attachment pages in my galleries
2. send me the url of the page it was clicked on so I can see which image is being ordered
3. allow me to use coupon codes for discounts
and
5. allow customers to opt into email marketing.
And that is it. I don’t want to redesign my site with a complex shopping card plugin, I don’t want to upgrade to a new version as I have done lots of work to my current template, I just need some way to do the 4 things I’ve mentioned, along with gathering the customer’s address so I can send them their prints once they’ve ordered them.
Suggestions would be helpful, everything I’ve looked at is either too complex for my needs, requires a site overhaul, or an upgrade. I just want it so that if someone looks at a specific image, they have the option to purchase a print. I would like something that works with the system that’s already in place.