BuyDig offers the FiiO E11K Kilimanjaro Portable Amplifier for $45.99 with free shipping. That's the lowest total price we could find by $14. It features an aluminum-alloy body, ALPS potentiometer, OPA1642 op-amp, and the ability to drive headphones between 16 and 150 Ohms.
Also available is the FiiO D03K Taishan Digital-to-Analog Audio Coverter for $24.95 with free shipping. That's the lowest total price we could find by $3. It features optical and coaxial inputs and supports bitrates of up to 192KHz/24bit.