This is a very good cart plugin to use with the Nextgen Gallery plugin. Intergration is relatively simple allowing you turn a photo gallery into an online shop with paypal payment.
I needed a reliable cart function for the Martin Phillips Studio project and this fitted the bill perfectly. You create Nextgen galleries in the normal way and then use a shortcode to apply pricing to the photos, making it incredibly client friendly. It’s ideal for a photography site as you can specify a range of pricing for different print sizes.
The support is also first-rate. The plugin didn’t have a feature I required so I emailed the author and within 48 hours an upgraded version was available for download.
Visit the plugin site here: eStore plugin.