In all honesty, probably not much at all, especially if it's the MechAssault bundle. Sorry brah.
classic live is shut down. only single player portions are useful now, unless lucky enough to have an xbox lan party around.
Lum fan.
Apparently around $30.
http://www.ebay.com/itm/new-xbox-liv...2#ht_64wt_1285
http://www.ebay.com/itm/XBOX-LIVE-12...#ht_137wt_1285
Of course you haven't mentioned if yours has everything included, or if the subscription card is used or not.