Musical keyboard stand and a piece of plywood.
[Link: amazon.com]

Adjustable height from standing to coffee table style.
Cheap, compact, lightweight, and if you cut/drill/mar the top, easy to replace.
Cut a 2" hole in the corner of the top for a handle, cord organization, clamping, etc., and a couple 1/2" holes for screwdrivers etc.
Plywood also doubles as a protector when working on counters etc.

Also great for setting receivers on when working in cabinets, or a test monitor stand, calibration mic holder, laser level platform...

Bucket seat optional.