I needed a stereo in the den of my new home and did not really want to spend much money. When moving I found a older car stereo I no longer used and a few speakers. I also knew I had a old PSU laying around so I decided to make a cheap stereo out of things I had. I spent $5 total on building this and it took me just a few hours.

Supplies
Car Stereo
Speaker Wire
Car Speakers
Speaker boxes (homemade is an option)
A PSU
A box to put them in (make sure to measure the size of your stereo plus your PSU, which I failed to do)
Wire strippers and crimps
Something for cutting the box.

Step 1: Gather Supplies

Get all the things needed to begin.

Step 2: Which Wires Go Where??

*Make sure PSU is NOT plugged in to anything!!!*

To begin. Get the big plug from the PSU containing many different colored wires. You only need 2 for this. The green one and any black one. All black are ground. You have two options.
1) Connect the 2 pins like in the picture
or
2) Cut the 2 wires, strip them, crimp the together.

I did option 2 because it seems less likely to come apart.

Next
From the other set of cables on the PSU choose one black and one yellow. Strip both of these. They will be needed in the next step.

Car Harness

From the car harness get your yellow and red wire (usually its these colors) Strip them about an inch down and twist them together.
Next connect these with the yellow from the PSU and crimp these together.

Get the black ground wire from the harness and strip it and connect it with the black from the PSU.

If done correctly you can now test out the unit. Plug in power to PSU and the harness to stereo. It should power on if done correctly.

Step 3: The Box

I used a wooden box from Michael's that I got for $2.50 with a coupon that comes every week in the mail :]

Measure twice cut once
Do as I say, not as I do.
I measured the stereo and then roughly measured on the box. I cut a bit smaller than needed because making the hole bigger is easier than cutting a whole nex box.

I used a x-acto knife and a pocket knife because that's all I had available at the time and it did a horrible job. But for me this is more of a temporary installation so that's okay.

Cut a hole for the PSU plug also.

Vent Holes
Drill plenty of vent holes for the PSU fan to blow out. Cutting out a square might be even better. More than what i did is definitely needed.

Holes for the wires are also a necessity. Size depends on wire thickness.

Step 4: Assemble

Put everything in the box and if done right should come out good. (Unlike mine.)

Step 5: Wiring Speakers

You can run as many speakers as allowed by your headunit. I have 4 extra Sony XPLODs laying around but only wanted 2. They are more than enough for me. Seeing as how they are new they were still in the cardboard boxes so i cut out a hole and left them there. The "box" does the job.

To wire them follow your headunit instructions. Simple enough. You can add front and rear speakers for surround sound if wanted. If you have and AUX port on it then you can plug it in to your TV and have a surround sound system.

Step 6: Pros and Cons

The Current setup is a simple practice run. I plan on getting real speaker boxes and a bigger box for the headunit and properly cutting it. This will all be at a later time.

Pros:
Can run multiple speakers. I can run 4 and have heard off some people running a sub and amp too!
Can use old materials and be even cheaper!
I can watch videos on mine and it has radio and AUX in and a SD card slot!
Mine actually has RCA inputs so if I wanted to I could plug in any RCA out device and view it on the 8" screen.

Cons:
Sound quality depends on quality of materials, so this can go both ways.
If you dont have any of these things it can be pricey.
You have the chance of frying your equipment if done wrong.

I personally like this and can post a video of it in action if requested by anyone.

Hopefully you enjoyed my first 'ible and maybe I'll make a version 2 someday.
Thanks for viewing :]