CartThrob works the way you do. Whether you want a single-page checkout, or a multi-page product configurator, CartThrob can handle it.

Using the power of ExpressionEngine and CartThrob, your store looks and works exactly like you envision it. Create your unique shopping experience with EE's built in templating system. Store orders and manage products using standard weblog entries.
CartThrob stores can look just like your site because they're truly integrated. CartThrob lets you make the most of your ExpressionEngine website.

CartThrob calculates shipping and tax, creates and processes coupons, stores orders, products, configured items, sends receipts and more. CartThrob has all of the features you'd expect of a traditional shopping cart, without any of the overhead.
Create related products, upsells, cross sells, options and add-ons. Display categories, user reviews, comments, and ratings. Customized orders, unique products, and integration with third party systems are all possible with CartThrob. You can sell classified ads, software, take donations, monetize your content, and even use your cart to give products away.

CartThrob has a plugin architecture which allows you to add payment gateways, and shipping options that work interchangably. CartThrob offers integrated credit card payment processing using common payment gateways including Authorize.net, Paypal Pro, Transaction Central and Sage! CartThrob can be used internationally, and will allow you to change payment processors on the fly, or provide your customers with multiple payment and shipping options.

Most carts have a zillion features out of the box, and most business don't need or want all of those features. Many times those features look great, but they don't work quite the way you wish they would. Like ExpressionEngine, CartThrob lets you build from an empty canvas, you pick and choose only the features you need.
Start from scratch and build a truly unique experience, or use CartThrob's sample template to start selling in minutes.