SOrry about the slow answer....
Looks like a bargain, as long as shipping doesn't eat you alive.
Chinese Elms have one major vice. Once you trim them, if you turn your back, you have to trim them again!
You'll find great articles about care and training of them on this site by Thomas J. Also on the
Dallas Bonsai Garden site .
As for wintering, some leave them out for some modest cold snaps, then bring them in. Ask at your local club and at nurseries in your area. The ones I work with live in a greenhouse year-round (they're not mine), so I can't really advise you on this.