Fry's has Duron 1.8ghz (bare) + ECS K7VTA3 8.0c MOBO for $49.99 until Thursday, 1-15. Limit is 1 and it says there are no rainchecks, so i guess you need to call them and make sure that they have some before you go..
Link to LA Times (under Technology -> Fry's)
Link to LA Times (under Technology -> Fry's)