3rd Party Shopping carts...don't know enough PHP/mysQL


I’m interested in implementing a shopping cart system to a couple web sites I’ve been working on.

I’ve looked into creating a custom mySQL/php interface and database, but it’s just way out of my league. i know that turntable lab uses virtual cart, but I’m not a big fan of subscription services. Anything open source or relatively inexpensive? FTR, both sellers are fine with using Paypal.

A BIG concern for me is being able to create and apply styles so that things look consistent with other parts of the site. I’ve been using a Paypal shopping cart system that my hosting service offers, but it’s very limited and the styles are not changeable and neither are shipping options.

Much thanks!