Lifetime License Single Domain.
I found this great deal at Hiolo.com who is an authorised reseller of Pinnacle Cart. The lifetime license for your domain is currently priced at $797 on the http://www.pinnaclecart.com/pinnacle-cart-licensed-solutions.htm Pinnacle Cart's website.
Sell anything from general merchandise to digital downloads, sell gift certificates and take payments in real time with a huge selection of payment gateways including the most popular PayPal and Google Checkout. SEO friendly.
In the latest version of the cart 3.7.9 customers can now shop from their mobile phones and tablets.
Pinnacle cart is packed with powerful features, to learn more about them see http://www.hiolo.com/pinnacle-cart.