Table top standing desk converter adjusts +20" - $50 (Tam Valley)

Get your standing hours in while working with your monitors at eye level.
Fully collapsed, the deck top is around 5" above your tabletop; when raised to it's full height, the deck is some 20" taller.
Tubular steel frame with pneumatic piston (manual, like an office chair, not electric) scissor lift adjusts height of work surface to as much as 20" above tabletop height.
Deck has a slot for holding phones and tablets upright, room for 2 mid-size monitors.
Drawer for keyboard and mouse, with gel wrist rest, is mounted on the deck's underside.
Decks are white laminate over fiberboard, main surface measures ~ 34 x 15 inches.
Comes assembled and weighs around 30 pounds.
Originally purchased from Amazon for $194.
Cash only.