This is a Japanese Maple I bought online from a Bonsai webshop. Although I was a bit apprehensive at first of buying trees online I had a good first experience with this one. As long as you are certain the supplier is trustworthy and delivery conditions are optimal you can be confident in this type of transaction.
First make sure you inspect the tree by a 360° pictures set. With deciduous trees it's best to see the tree without its leaves, so that you have a good view of the branch structure.
This tree is about 25 years old. As you can see it hasn't got a conventional structure but that's just why I like it. Still some work to do though..