MarketPress by WPMU DEV is actually a pretty great e-commerce plugin. There is the free ‘lite’ version and a premium ‘subscription’ based version. We used the ‘lite’ version for e-commerce at comics-etc. and where quite impressed.
There where, however, an few issues. The first was not being able to delete test orders. It seems that officially, the only way to delete an order is to use phpMyAdmin and manually remove orders from the database. It is interesting to note, that months ago, Aaron (one of the MarketPress developers) mentioned that he has added this to his to-do list for feature requests.
We went ahead and added this feature and let the developers know on the WordPress Forum in this post. To date: crickets….
Also, to use this plugin in a language other than English—the official response was ‘do it yourself’. Despite numerous requests, WPMU DEV has yet to provide a language repository for people to share language packs. With this in mind, we have created an unofficial Language Repository for MarketPress purely out of our own frustration. Yay WordPress community—WPUMDEV: not so much.