B&H Photo Video offers the FiiO E18 Kunlun USB-Rechargeable Portable Headphone Amplifier / DAC for $99.95 with free shipping. (All About Office via Amazon has it for the same price with free shipping.) That's $20 under our December mention, which was bundled with a microSD card, and the lowest total price we've seen. (It's the best deal now by $8.) Designed for Android devices, it features controls for bass, treble, and gain, and can also be used to charge your smartphone.