Walmart offers the XO Vision Automotive Digital Media Receiver, model no. XD103, for $19.88. (Amazon has it for the same price via Prime, although stock is very limited.) Opt for free in-store pickup to avoid the $4.97 shipping charge. That's tied with our mention from ten days ago and the lowest total price we could find by $10. This MP3 stereo receiver features 80 watts of maximum power, a USB port, SD card slot, FM tuner with 18 presets, and auxiliary port.