I did not have the skill/money/time to build a full sized TARDIS. So I built 1/5 of a TARDIS, not a 1/5 scale TARDIS, just the top part. I did not make a particular model of TARDIS, I just got as close as I could with the pieces I had. The dimensions were based on what I had and with the least amount of cuts. I salvaged the wood and the screws from my daughter's old bed frame. The only materials I bought were the acrylic sheet (about $12) for the police box signs and the paint, which were two 8 oz tester jars ($2.96 a piece). I used the wood from the bed and some leftover luan plywood and MDF. The light cover is a made from an old "jelly jar" outdoor light fixture, MDF, a plastic cap, and four chop sticks. The light inside is from some cheap/gimmicky computer speakers that respond to sound. I used an old "gum stick" iPod shuffle with various TARDIS SFX and few silent mp3s. I didn't want it playing constantly and it was a quick way to create a random soundtrack. To create the police box signs I printed out the lettering from my inkjet and used rubber cement to stick them to the acrylic. I then used an x-acto to cut around the letters and spray painted the back all black. After a few light coats I removed the letters and glue and painted the back white.
I dug up bit of the grass in the front yard to make it look like it had materialized partially submerged in the ground. In the dark it looked pretty good.