Ok, I overlooked the "mini system" part of the request. I bet you would have a hard time beating this for $289 plus shipping costs.
$200 bucks for this (new/sealed)Athena ASP400 subwoofer on audiogon
http://www.hometheatersound.com/equipment/athena_audition_asp400.htm
$89 bucks for these Athena AS B1's on Audiogon
http://www.soundstage.com/revequip/athena_asb1.htm
good luck ;)