Free version only holds 10 carts in memory. Also, every time you look at the app it pops up and asks you if you'd like to upgrade. It wasn't enticing, just annoying. Instead, I went with Persistent cart which does unlimited carts for free.
Does not seem to do anything. I can log into one machine create an order, log into another machine and the items are not there.
Perhaps there is some conflict with another app....
Seems like it would be a good thing to have built into shopify once you have users create accounts.