GWagen models totally for free
Yes, though a little bit of DIY-skills are required:
http://www.racepaper.de/street/polizei/download/mb_g2.pdf
http://www.racepaper.de/street/polizei/download/mb_g4.pdf
http://www.racepaper.de/street/militar/download/g_mod_1.pdf
http://www.racepaper.de/street/militar/download/g_mod_2.pdf
I printed the model in my colour EPSON printer in thin carton and let it to dry for about 1 week. I used Super Glue 3 (all my fingers are still glued to one another). The problem is that you need a carton thick enough to add rigidity to the final product and then it is impossible to bend. But I had a great time and am very proud of my botch job.
Plenty of other models here: http://www.streetpaper.de/
This is freeware and therefore cannot be sold. This is a warning for unscrupolous Ebayers who want to make money out of everything.
Enjoy!