My sub $10 mount. Tablet stays in its cover. Two strips of Velcro and a chunk of sponge between the dash panel and the cover to keep it all tensioned. Two metal brackets made from scrap and some more Velcro inside the cover to stop any fore/aft movement, stops it hitting the radio.
Velcro wraps around the dash panel, so this only works for 2007-2010 models