Commonly sold as a "money tree" this is a pachira that would probably grow better if you just treat it as a regular houseplant rather than a bonsai. It requires high humidity.

From Wikipedia:
Pachira aquatica is a tropical wetland tree of the mallow family Malvaceae, native to Central and South America where it grows in swamps. It is known by the common names Malabar chestnut, Guiana chestnut, provision tree, saba nut, monguba (Brazil), pumpo (Guatemala) and is commercially sold under the names money tree and money plant. This tree is sometimes sold with a braided trunk and is commonly grown as a houseplant, although more commonly what is sold as a "Pachira aquatica" houseplant is in fact a similar species, P. glabra.

Hi, your plant is most definately what is commonly called a "Ginseng Ficus". Care is the same as the regular ficus. This ficus grows amazing fat roots.
You can put in window, or under lights for the winter and back out in summer.
Ficus retusa var. Ginseng

Nice find for $2!

I see that caudiciformken is right and I was wrong. The pachira has palmate leaves, which your plant does not. My bad. If you search retusa on this forum, you will find many discussions about caring for it.

Hope you can salvage this tree! Make sure you buy a pot with drainage holes and look up information on suitable bonsai soil for it.

I usually mix my own using 1 part granite and 1 part potting soil for a basic mix.

Good luck!