Secondipity via eBay offers the refurbished Sony SRS-X55 30-watt 2.1-Channel Bluetooth Speaker in Black for $79.99 with free shipping. That's at least $75 less than you'd pay for a new unit. It features two 1.5" drivers, one 2.28" subwoofer, two passive rear-facing bass radiators, up to 10 hours of playback per charge, NFC pairing, speakerphone capability, and 3.5mm auxiliary input.

A 90-day Liquidity Services warranty applies.