TigerDirect offers the AMD A10-5800K Trinity 3.8GHz Socket FM2 Quad-Core Unlocked Desktop Processor, model no. AD580KWOHJBOX, for $79.99 with free shipping. That's $10 under our mention from August and the lowest total price we've seen. (It's also the best price we could find by $5, although most merchants charge $95 or more.) It has a 4MB L2 cache and 4.2GHz boost speed.
Update: Specs corrected.