Yes, the Order Manager works with Amazon Marketplace and zShops. It can also import orders for Amazon Sellers Central merchants with text file accounts, although it cannot yet send status info back to Amazon for them. For Sellers Central merchants with XML accounts, we can import orders and automatically send status data back to Amazon, but there are some additional software requirements. You can find more info in our Knowledge Base at:
http://www.stoneedge.com/support/amazonsetup.html and
http://www.stoneedge.com/support/wash.html.
Once you purchase the Order Manager for one shopping cart (e.g. MonsterCommerce) there is a $300 fee for each additional shopping cart (e.g. Amazon, Shop.com, Yahoo!Store, etc.) that you want to use. The three Amazon store types are covered by one $300 fee.
There are no per-store charges, so if you have more than one MonsterCommerce store you don't have to pay any extra to manage all of them with the Order Manager, as long as you do it from one office location.
Finally, you can set up separate Order Manager "stores" for each shopping cart that you import from, or import multiple stores (e.g. 2 MC stores and an Amazon store) into the same Order Manager store. In that case, the Order Manager will keep track of the source of each order, and you can use different company names, etc. in emails and on invoices and packing slips depending on the source of each order.
You can find more info on the Order Manager itself at www.StoneEdge.com/OrderManager.htm.