Crutchfield
Top of the line stereo for less than $200. You supply make and model of your vehicle and it will come with everything you need for install; detailed instructions with pictures, any pieces needed to fit in your dash, wire harness, everything. Fast shipping.
If you're going aftermarket and have some basic skills, agree 100%.
Crutchfield, while not the cheapest, is a top-notch company with great customer service.

Maybe not the cheapest, but, I have a hard time figuring out how much money I need to save on a $129 stereo that's guaranteed to come with all the parts and pieces needed for your make an model. One missed piece and the time I wasted just surpassed any savings.
And great point with customer service, just a phone call away for any question, like steering wheel controls.